Cannabis Psychosis Research

Altered Neurobehavioral Reward Response Predicts Psychotic-Like Experiences in Youth Exposed to Cannabis Prenatally.

Amir, Carolyn M · 2026

Prenatal cannabis exposure (652 youth) was longitudinally associated with psychotic-like experiences, mediated by blunted striatal activation during reward anticipation — a marker of disrupted endocannabinoid-dopamine function..

Cannabis Use Among Individuals With Psychosis After State-Level Commercial Cannabis Legalization.

Hyatt, Andrew S · 2026

Individuals with psychosis in recreational cannabis legalization states increased 30-day cannabis use by 9.53 percentage points (95% CI=3.05-16.00, p=0.004), with sensitivity analyses showing significant increases after retail outlets opened but not before, and no changes in higher-frequency use..

Prevalence of schizophrenia spectrum and bipolar disorder among patients with cannabis induced psychosis: a systematic review and meta-analysis.

Javed, Mohammad Saad · 2026

Pooling data from 13 studies with a total of 7,515 patients diagnosed with cannabis-induced psychosis, this meta-analysis calculated the rates at which these individuals later received diagnoses of schizophrenia spectrum disorder or bipolar disorder. The conversion rates were substantial.

Psychological and Psychosocial Interventions for People With Schizophrenia and Co-Occurring Substance Use Disorders: A Systematic Review and Meta-Analysis.

Salahuddin, Nurul Husna · 2026

A very small effect favoring interventions was observed for overall symptoms (SMD -0.11, 95% CI -0.27 to 0.05, low confidence), mainly driven by nicotine studies.

Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders.

Young-Wolff, Kelly C · 2026

This large longitudinal cohort study followed adolescents aged 13–17 who were screened for past-year cannabis use during routine pediatric care at Kaiser Permanente Northern California from 2016 to 2023, with follow-up through age 25. Adolescents who reported cannabis use had significantly higher rates of clinician-diagnosed psychiatric disorders compared to non-users.

The association between cannabis use and paranoia: Meta-analysis of experimental and observational studies.

Belvederi Murri, Martino · 2025

Five experimental studies showed that cannabinoid recipients developed more severe paranoia than placebo (SMD=0.47).

Cannabis Use Cessation and the Risk of Psychotic Disorders: A Case-Control Analysis from the First Episode Case-Control EU-GEI WP2 Study: L'arrêt de l'utilisation du cannabis et le risque de troubles psychotiques: Une analyse cas-témoins tirée de l'étude cas-témoins EU-GEI WP2 centrée sur les premiers épisodes psychotiques.

Bond, Benjamin W · 2025

Ex-users who stopped 1-4 weeks prior had 6.9 times the psychosis odds of never-users.

Randomized Laboratory Study of Single-Dose Cannabis, Dronabinol, and Placebo in Patients With Schizophrenia and Cannabis Use Disorder.

Brunette, Mary F · 2025

Oral dronabinol (15 mg) worsened verbal learning (B = -9.89) and attention (B = -0.61) in the schizophrenia-CUD group compared to placebo.

Does cannabidiol reduce the adverse effects of cannabis in schizophrenia? A randomised, double-blind, cross-over trial.

Chesney, Edward · 2025

CBD pre-treatment resulted in worse delayed verbal recall (3.5 vs 4.8 words, p=0.001) and greater increase in positive psychotic symptoms (5.0 vs 2.9 PANSS-P increase, p=0.01) compared to placebo pre-treatment; CBD did not alter THC or 11-OH-THC plasma levels..

Associations between cannabis-related hospital visits and psychotic disorder-related hospital visits in Arizona from 2016 to 2022.

Colby, Alana M · 2025

Cannabis-related hospital visits were approximately 7 times as likely to involve a psychotic disorder diagnosis as cannabis-unrelated visits, an association that remained stable from 2016 to 2022.

Relapse in substance-induced psychosis and associated risk factors. A Nationwide register-linkage study from Sweden.

Ellilä, Venla · 2025

Cannabis-induced psychosis carried a 2.42x higher risk of relapse compared to alcohol-induced psychosis.

Cannabis legalization and cannabis use disorder in United States Veterans Health Administration patients with and without psychiatric disorders, 2005-2022: a repeated cross-sectional study.

Hasin, Deborah S · 2025

CUD prevalence among veterans with any psychiatric disorder rose from ~3.3% in 2005 to ~5.7-6.4% by 2022, depending on state legalization status.

Systematic review of risk factors for violence in psychosis: 10-year update.

Lagerberg, Tyra · 2025

Criminal history factors had the greatest risk (pooled OR 3.50, 95% CI: 2.37-5.16), followed by substance misuse (OR 2.36, 95% CI: 1.99-2.80).

Systematic review and meta-analysis on the effects of chronic peri-adolescent cannabinoid exposure on schizophrenia-like behaviour in rodents.

Li, Zhikun · 2025

Across 359 experiments from 108 articles, CB1 receptor agonists (both natural and synthetic cannabinoids) during adolescence impaired working memory (g=-0.56), novel object recognition (g=-0.66), novel object location recognition (g=-0.70), social novelty preference (g=-0.52), social motivation (g=-0.21), pre-pulse inhibition (g=-0.43), and sucrose preference (g=-0.87).

Trends in cannabis-attributable hospitalizations and emergency department visits: data from the Canadian Substance Use Costs and Harms Study (2007-2020).

Malam, Raadiya · 2025

Between 2007 and 2020, cannabis-attributable inpatient hospitalizations increased from 6.4 to 14.0 per 100,000, while ER visits rose from 52.1 to 111.0 per 100,000.

Cannabis Withdrawal and Psychiatric Intensive Care.

Malik, Aliyah · 2025

Among 52,088 psychiatric admissions in London over 16 years, cannabis users were 44% more likely than non-users to require psychiatric intensive care overall.

Cannabis use, health problems, and criminal offences in Germany: national and state-level trends between 2009 and 2021.

Manthey, Jakob · 2025

Age-standardized cannabis use prevalence nearly doubled (5.7% to 10.6%), cannabis-related diagnoses more than tripled (1.1 to 3.7 per 1,000), and minor possession offences increased (1.8 to 3.1 per 1,000) between 2009 and 2021.

Cannabis use and suicide in people with a diagnosis of schizophrenia: a systematic review and meta-analysis of longitudinal, case control, and cross-sectional studies.

Mulligan, Lee D · 2025

Across 29 studies (36 samples), cannabis use was associated with 40% higher odds of attempted suicide (OR=1.40, 95% CI: 1.16-1.68) and 21% higher risk of suicide death (HR=1.21, 95% CI: 1.04-1.40).

Changes in Incident Schizophrenia Diagnoses Associated With Cannabis Use Disorder After Cannabis Legalization.

Myran, Daniel T · 2025

The population-attributable risk fraction (PARF) for CUD associated with schizophrenia nearly tripled from 3.7% pre-legalization to 10.3% post-legalization.

Psychosis Spectrum Symptoms Before and After Adolescent Cannabis Use Initiation.

Osborne, K Juston · 2025

Adolescents who used cannabis at any point had more psychosis symptoms (B=0.86) and distress from symptoms (B=1.17) than never-users, consistent with shared vulnerability.

Does Cannabis Use Contribute to Schizophrenia? A Causation Analysis Based on Epidemiological Evidence.

Pourebrahim, Sepehr · 2025

Analysis of 18 qualifying studies (10 included in forest plot) found all reported increased risk for psychosis-like events or schizophrenia with cannabis use, with 9 of 10 reaching significance.

The psychosis continuum: Systematic review on prodromal markers, symptom progression, and early intervention strategies.

Ricci, Valerio · 2025

This systematic review synthesized 60 studies spanning 25 years (2000–2025) to map the trajectory from early warning signs to full psychotic episodes.

Co-occurrence between adverse childhood experiences and cannabis use in psychosis risk and course: A stratified systematic review.

Ricci, Valerio · 2025

Across 62 studies in five population categories, childhood adversity and cannabis use showed synergistic psychosis risk amplification: odds ratios up to 20.9 in community samples and 31.0 in first-episode samples.

Cannabis and suicide risk in first-episode psychosis: Mechanisms, interactions, and intervention strategies.

Ricci, Valerio · 2025

Across 50 studies (12,764 FEP patients), cannabis use consistently elevated suicide risk (OR 1.43-1.84), with daily use showing OR 2.73 (95% CI 1.89-3.94) and high-THC cannabis OR 3.12 (95% CI 2.11-4.62).

Novel psychoactive substances and psychosis: A comprehensive systematic review of epidemiology, clinical features, neurobiology, and treatment.

Ricci, Valerio · 2025

Among 85 studies, synthetic cannabinoids showed consistently higher psychosis risk than traditional cannabis (OR 4.4-5.2 for synthetic cannabinoids vs cannabis).

High-Concentration Delta-9-Tetrahydrocannabinol Cannabis Products and Mental Health Outcomes : A Systematic Review.

Rittiphairoj, Thanitsara · 2025

In non-therapeutic studies, high-concentration THC showed unfavorable associations with psychosis/schizophrenia (70% of studies) and cannabis use disorder (75%).

Antipsychotic Use and Psychiatric Hospitalization in First-Episode Non-affective Psychosis and Cannabis Use Disorder: A Swedish Nationwide Cohort Study.

Denissoff, Alexander · 2024

Any antipsychotic use reduced psychotic relapse risk by 33%.

Medical cannabis authorization and risk of emergency department visits and hospitalization due to psychotic disorders: A propensity score-matched cohort study.

Dubois, Cerina · 2024

Medical cannabis patients had a psychotic disorder incidence of 3.00 per 1,000 person-years compared to 1.88 in controls.

Use of antipsychotic medication, benzodiazepines, and psychiatric hospitalization in cannabis-related versus cannabis-unrelated schizophrenia - a nationwide, register-based cohort study.

Hjorthøj, Carsten · 2024

Among 35,714 people with incident schizophrenia (11.5% cannabis-related), propensity-score matched analysis showed cannabis-related cases used significantly less antipsychotics and benzodiazepines.

Behind the heterogeneity in the long-term course of first-episode psychosis: Different psychotic symptom trajectories are associated with different patterns of cannabis and stimulant use.

Kreis, Isabel · 2024

Four trajectories emerged: Stable Remission (54.2%), Delayed Remission (15.6%), Psychotic Relapse (7.8%), and Persistent Symptoms (22.4%).

Frequency and patterns of substance-induced psychosis in persons with concurrent mental health and substance use disorders during the COVID-19 pandemic: A Norwegian register-based cohort study.

Leonhardt, Marja · 2024

Despite fewer individuals being diagnosed with substance-induced psychosis (SIP) during COVID, total SIP episodes increased.

Age-dependent association of cannabis use with risk of psychotic disorder.

McDonald, André J · 2024

Among 11,363 Ontario youth, cannabis use was associated with 11.2-fold increased psychosis risk during adolescence (12-19) but only non-significant 1.3-fold during young adulthood (20-33).

The contribution of cannabis use to the increased psychosis risk among minority ethnic groups in Europe.

Selten, J P · 2024

The odds ratio for psychotic disorder among non-Western minorities was 1.80, and adjusting for cannabis use frequency barely changed it (1.81).

Differential associations of adolescent versus young adult cannabis initiation with longitudinal brain change and behavior.

Albaugh, Matthew D · 2023

Adolescent cannabis initiation (14-19) was associated with cortical thinning in dorsolateral and ventrolateral prefrontal cortex that persisted into young adulthood and partially mediated associations with later cocaine, ecstasy, and cannabis use at age 22.

Association between cannabis use and symptom dimensions in schizophrenia spectrum disorders: an individual participant data meta-analysis on 3053 individuals.

Argote, Mathilde · 2023

Cannabis use was associated with higher positive symptom severity (aMD=0.38), lower negative symptom severity (aMD=-0.50), and higher excitement (aMD=0.16) using the 5-factor PANSS model.

The relationship between cannabis use, schizophrenia, and bipolar disorder: a genetically informed study.

Cheng, Weiqiu · 2023

Genome-wide genetic correlations between psychotic disorders and cannabis phenotypes ranged from 0.22-0.35.

Characterization of childhood trauma, hippocampal mediation and Cannabis use in a large dataset of psychosis and non-psychosis individuals.

Del Re, Elisabetta C · 2023

Among 1,185 participants (397 controls, 209 bipolar-I, 279 schizoaffective, 300 schizophrenia), cannabis use and childhood trauma interacted in survival analysis to predict earlier psychosis onset.

Transition to Schizophrenia Spectrum Disorder Following Emergency Department Visits Due to Substance Use With and Without Psychosis.

Myran, Daniel T · 2023

Among 9.8 million people without prior psychosis, those with ER visits for substance-induced psychosis had a 163-fold increased risk of transitioning to schizophrenia (3-year risk: 18.5% vs 0.1%).

Association between non-medical cannabis legalization and emergency department visits for cannabis-induced psychosis.

Myran, Daniel T · 2023

Across 6,300 ER visits for cannabis-induced psychosis, restricted legalization showed no change relative to pre-legalization.

Risk of readmission among individuals with cannabis use disorder during a 15-year cohort study: the impact of socio-economic factors and psychiatric comorbidity.

Rabiee, Rynaz · 2023

About 80% of CUD visits were outpatient.

Annual incidence of substance-induced psychoses in Scandinavia from 2000 to 2016.

Rognli, Eline Borger · 2023

Cannabis-induced psychosis incidence increased in all three countries: Denmark (2.6 to 5.6), Sweden (0.8 to 2.7), Norway (1.8 to 3.0 per 100,000).

Association between formal thought disorder and cannabis use: a systematic review and meta-analysis.

Argote, Mathilde · 2022

Cannabis users had higher FTD severity overall (SMD 0.21, 95% CI 0.12-0.29, p=0.00009).

Associations Between Canada's Cannabis Legalization and Emergency Department Presentations for Transient Cannabis-Induced Psychosis and Schizophrenia Conditions: Ontario and Alberta, 2015-2019.

Callaghan, Russell C · 2022

Cannabis-induced psychosis ED presentations doubled between April 2015 and December 2019.

Consensus paper of the WFSBP task force on cannabis, cannabinoids and psychosis.

D'Souza, Deepak Cyril · 2022

Converging evidence supports that cannabis increases psychosis risk across a spectrum from transient states to chronic psychosis.

Timing of cannabis exposure relative to prodrome and psychosis onset in a community-based first episode psychosis sample.

Kline, Emily R · 2022

Cannabis exposure (78%) and cannabis use disorders (47%) were highly prevalent at first-episode admission.

A Nationwide Study of Inpatient Case Rate Incidence of Cannabis-Related Diagnoses in Switzerland.

Pfeifer, Philippe · 2022

Cannabis-related psychiatric hospitalization rates increased significantly from 1998 to 2020.

Longitudinal effects of cannabis use on attentional processes in patients with first episode of psychosis.

Setién-Suero, Esther · 2022

Over 3 years, attention improved most in FEP patients who never used cannabis (n=238), followed by ex-users (n=105) and persistent users (n=43).

Genome-wide identification of the shared genetic basis of cannabis and cigarette smoking and schizophrenia implicates NCAM1 and neuronal abnormality.

Song, Weichen · 2022

A common genetic factor of cannabis and cigarette smoking explained 8.6% of schizophrenia heritability.

The association of cannabis use with quality of life and psychosocial functioning in psychosis.

Bruins, J · 2021

Cannabis users (11.4%) had significantly lower quality of life (B=-2.93) and worse psychosocial functioning (B=1.03) than non-users.

Annual incidence of cannabis-induced psychosis, other substance-induced psychoses and dually diagnosed schizophrenia and cannabis use disorder in Denmark from 1994 to 2016.

Hjorthøj, Carsten · 2021

Cannabis-induced psychosis incidence more than doubled from 2.8 per 100,000 in 2006 to 6.1 per 100,000 in 2016.

No evidence of associations between genetic liability for schizophrenia and development of cannabis use disorder.

Hjorthøj, Carsten · 2021

Schizophrenia polygenic risk scores did not predict CUD in controls (HR=1.16, not significant) or in patients with other psychiatric disorders.

The relationship between cannabis and schizophrenia: a genetically informed perspective.

Johnson, Emma C · 2021

Genetic liability to CUD predicted schizophrenia (beta=0.29, p=0.001) even after accounting for cannabis ever-use, tobacco smoking, and nicotine dependence.

How High? Trends in Cannabis Use Prior to First Admission to Inpatient Psychiatry in Ontario, Canada, between 2007 and 2017.

McGuckin, Taylor · 2021

Cannabis use within 30 days of first psychiatric admission rose from 16.7% in 2007 to 25.9% in 2017.

Precursors of self-reported subclinical hypomania in adolescence: A longitudinal general population study.

Nielsen, Louise Gunhard · 2021

Cannabis use by age 15 was a strong independent predictor of self-reported subclinical hypomania at age 16 (RR 3.14, 95% CI 1.93-5.10), after adjusting for age 11 psychopathology and other precursors.

The continuity of effect of schizophrenia polygenic risk score and patterns of cannabis use on transdiagnostic symptom dimensions at first-episode psychosis: findings from the EU-GEI study.

Quattrone, Diego · 2021

Schizophrenia polygenic risk score (SZ-PRS) was associated with both negative (B=0.18) and positive (B=0.19) symptom dimensions in 617 first-episode patients, regardless of diagnostic category.

Daily use of high-potency cannabis is associated with more positive symptoms in first-episode psychosis patients: the EU-GEI case-control study.

Quattrone, Diego · 2021

In patients, daily high-potency cannabis use was associated with the highest positive symptom scores (B=0.35, 95% CI 0.14-0.56) in a dose-response pattern.

Association of extent of cannabis use and psychotic like intoxication experiences in a multi-national sample of first episode psychosis patients and controls.

Sami, Musa · 2021

In the EU-GEI study across 15 sites and 6 countries, FEP patients (n=655) showed a steeper increase in psychotic-like intoxication experiences at higher cannabis use levels compared to controls (n=654), while euphoric experiences did not differ between groups..

Adolescent cannabis use and adult psychoticism: A longitudinal co-twin control analysis using data from two cohorts.

Schaefer, Jonathan D · 2021

In 1,544 twins, both cumulative adolescent cannabis use and cannabis use disorder were associated with higher adult Psychoticism scores, but comparing twins within pairs (where one used more cannabis) showed no within-pair difference, pointing to familial confounds rather than causal effects..

The Behavioral Sequelae of Cannabis Use in Healthy People: A Systematic Review.

Sorkhou, Maryam · 2021

Across 124 studies of cannabis effects in people without psychiatric or medical conditions, frequency of use, THC content, age of onset, and cumulative exposure all contributed to adverse behavioral outcomes including impaired cognition, motivation, mood, anxiety, psychosis risk, and psychosocial functioning..

Schizophrenia and the Environment: Within-Person Analyses May be Required to Yield Evidence of Unconfounded and Causal Association-The Example of Cannabis and Psychosis.

van Os, Jim · 2021

In the fixed-effects model, prior cannabis use predicted subsequent psychotic experiences (adjusted OR = 7.03, 95% CI: 2.39-20.69), but prior psychotic experiences did not predict subsequent cannabis use (adjusted OR = 0.59, 95% CI: 0.21-1.71)..

Cannabis, schizophrenia genetic risk, and psychotic experiences: a cross-sectional study of 109,308 participants from the UK Biobank.

Wainberg, Michael · 2021

Cannabis ever-use was associated with 67% greater adjusted odds of delusions of reference among individuals in the top fifth of schizophrenia polygenic risk, but only 7% greater adjusted odds among the bottom fifth.

Premorbid Adjustment and IQ in Patients With First-Episode Psychosis: A Multisite Case-Control Study of Their Relationship With Cannabis Use.

Ferraro, Laura · 2020

Psychosis patients who used cannabis occasionally or daily had better premorbid social adjustment than patients who never used.

Psychosis-Relevant Effects of Intravenous Delta-9-Tetrahydrocannabinol: A Mega Analysis of Individual Participant-Data from Human Laboratory Studies.

Ganesh, Suhas · 2020

44.75% of THC infusions produced clinically meaningful positive psychosis symptoms.

Cannabis use and psychosis: a review of reviews.

Hasan, Alkomiet · 2020

Across 26 reviews, the evidence consistently showed: psychosis occurs more frequently in cannabis users than non-users; risk increases with dose; cannabis users develop psychosis earlier; and cannabis use is associated with increased relapse, more hospitalizations, and more pronounced positive symptoms in those with psychotic disorders..

Psychiatric symptoms caused by cannabis constituents: a systematic review and meta-analysis.

Hindley, Guy · 2020

THC produced large effect sizes for total symptoms (SMC 1.10), positive/psychotic symptoms (SMC 0.91), and negative symptoms (SMC 0.78) compared to placebo.

Use of illicit substances and violent behaviour in psychotic disorders: two nationwide case-control studies and meta-analyses.

Lamsma, Jelle · 2020

Across two large nationwide samples (GROUP, Netherlands, N=871; NEDEN, UK, N=921), daily cannabis use was associated with 1.6 times higher odds of violence in people with psychotic disorders (pooled OR 1.6, 95% CI 1.2-2.0).

The influence of risk factors on the onset and outcome of psychosis: What we learned from the GAP study.

Murray, R M · 2020

In 410 first-episode psychosis patients and 370 controls in South London, approximately 25% of new psychosis cases were attributable to high-potency cannabis use.

Transition of Substance-Induced, Brief, and Atypical Psychoses to Schizophrenia: A Systematic Review and Meta-analysis.

Murrie, Benjamin · 2020

Across 50 studies encompassing 40,783 people, the pooled transition rate from substance-induced psychosis to schizophrenia was 25%.

Cannabis use disorders may protect against certain disorders of the digestive organs in people with schizophrenia but not in healthy controls.

Olesen, Julie Aamand · 2020

Among 21,066 schizophrenia cases and 176,935 matched controls, cannabis use disorders in schizophrenia patients were associated with decreased risk of gut-brain interaction disorders (IBS, dyspepsia; HR 0.84, p=0.003) and inflammatory bowel disease (HR 0.70, p=0.045).

Do cannabis use disorders increase medication non-compliance in schizophrenia?: United States Nationwide inpatient cross-sectional study.

Patel, Rikinkumar S · 2020

Among 1,030,949 schizophrenia inpatients (2010-2014), 26% were non-compliant with medications.

Cannabinoid receptor CNR1 expression and DNA methylation in human prefrontal cortex, hippocampus and caudate in brain development and schizophrenia.

Tao, Ran · 2020

CNR1 expression is high in fetal prefrontal cortex and hippocampus, then drops dramatically after birth.

Dark Classics in Chemical Neuroscience: Δ9-Tetrahydrocannabinol.

Banister, Samuel D · 2019

THC primarily acts as a partial agonist at CB1 receptors, producing its distinctive intoxication.

Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis.

Black, Nicola · 2019

Pharmaceutical THC (with or without CBD) produced only a very small improvement in anxiety among patients with other medical conditions (SMD -0.25).

The neuropsychopharmacology of cannabis: A review of human imaging studies.

Bloomfield, Michael A P · 2019

Cannabis and THC acutely affect executive, emotional, reward, and memory processing through direct CB1 effects and indirect effects on glutamate, GABA, and dopamine systems.

Association of Prenatal Cannabis Exposure With Psychosis Proneness Among Children in the Adolescent Brain Cognitive Development (ABCD) Study.

Fine, Jeremy D · 2019

Maternal cannabis use during pregnancy, particularly after the mother knew she was pregnant, was associated with higher psychosis proneness scores in their children, based on data from the large-scale Adolescent Brain Cognitive Development study..

Exposure to cannabinoids can lead to persistent cognitive and psychiatric disorders.

Krebs, Marie-Odile · 2019

Cannabis use is associated with dose-dependent cognitive deficits and a 2-fold or greater increase in psychosis risk.

Measuring Disturbance of the Endocannabinoid System in Psychosis: A Systematic Review and Meta-analysis.

Minichino, Amedeo · 2019

CSF anandamide was significantly elevated in schizophrenia (SMD 0.97, p<.001).

Acute Illness Associated With Cannabis Use, by Route of Exposure: An Observational Study.

Monte, Andrew A · 2019

Edible cannabis ER visits were disproportionate to sales (10.7% of visits vs 0.32% of THC sales).

Schizophrenia is associated with increased risk of subsequent substance abuse diagnosis: A nation-wide population-based register study.

Petersen, Stine Mai · 2019

Among 3.1 million individuals followed for over 100 million person-years, 14,007 developed schizophrenia, and 2,885 were subsequently diagnosed with substance abuse.

Stopping cannabis use benefits outcome in psychosis: findings from 10-year follow-up study in the PAFIP-cohort.

Setién-Suero, E · 2019

Persistent cannabis users had more severe symptoms (BPRS: p < .001; SAPS: p = .002) and poorer functioning (DAS: p = .048; GAF: p = .033) at 10 years compared to ex-users and never-users.

Risk factors and peripheral biomarkers for schizophrenia spectrum disorders: an umbrella review of meta-analyses.

Belbasis, L · 2018

Researchers conducted an umbrella review, a review of reviews, to systematically evaluate all published meta-analyses of non-genetic risk factors and biomarkers for schizophrenia spectrum disorders.

Meta-analysis of neurocognition in young psychosis patients with current cannabis use.

Bogaty, Sophia E R · 2018

Previous research had suggested that psychosis patients with lifetime cannabis use appeared to have better cognitive function than non-using patients.

Individual and combined effects of acute delta-9-tetrahydrocannabinol and cannabidiol on psychotomimetic symptoms and memory function.

Morgan, Celia J A · 2018

Forty-eight cannabis users were selected based on schizotypal personality scores and use frequency, then received four vaporized conditions in crossover design: placebo, THC 8 mg, CBD 16 mg, and THC 8 mg + CBD 16 mg. THC alone increased psychotic symptoms on the PSI, increased negative symptoms on the BPRS, and robustly impaired both episodic and working memory. Co-administration of CBD at a 2:1 ratio (16 mg CBD with 8 mg THC) did not attenuate any of these THC effects. CBD alone reduced PSI scores, but only in light cannabis users.

Cannabis consumption and psychosis or schizophrenia development.

Ortiz-Medina, María Bettina · 2018

Researchers reviewed 66 papers examining the relationship between cannabis use and psychosis in people without pre-existing schizophrenia. The main conclusion: cannabis use doubles the risk of developing psychosis in vulnerable individuals. Additional findings: - A dose-response relationship exists: heavier cannabis use is associated with greater psychosis risk. - Age of first use matters: earlier initiation is associated with higher risk. - Gene-environment interactions modulate the association, meaning genetic susceptibility influences how much cannabis increases individual psychosis risk. The evidence was drawn from 23 cohort studies (which follow people over time) and 43 reviews, representing a substantial evidence base accumulated over decades of research..

GWAS of lifetime cannabis use reveals new risk loci, genetic overlap with psychiatric traits, and a causal influence of schizophrenia.

Pasman, Joëlle A · 2018

In the largest GWAS of lifetime cannabis use to date, researchers analyzed 184,765 individuals and identified eight genome-wide significant SNPs in six genomic regions. All measured genetic variants combined explained 11% of the variance in cannabis use. Gene-based tests revealed 35 significant genes in 16 regions.

Are cannabis-using and non-using patients different groups? Towards understanding the neurobiology of cannabis use in psychotic disorders.

Sami, Musa Basseer · 2018

Cannabis use is associated with increased risk of developing psychotic disorders, increased hospitalization, longer hospital stays, and treatment failure.

Cannabidiol (CBD) as an Adjunctive Therapy in Schizophrenia: A Multicenter Randomized Controlled Trial

McGuire, Philip · 2018

In 88 patients with schizophrenia already on antipsychotics, adding 1000 mg/day CBD for 6 weeks significantly reduced positive psychotic symptoms (PANSS positive difference: -1.4, p=0.019) and increased clinician-rated improvement (OR 3.65, p=0.017) versus placebo.

Evidence for the Risks and Consequences of Adolescent Cannabis Exposure.

Levine, Amir · 2017

This comprehensive review examined four neuropsychiatric outcomes most vulnerable to adolescent cannabis exposure: cognition, emotional functioning, psychosis risk, and addiction. The clinical literature showed strong correlations between early, frequent, heavy adolescent cannabis use and poor cognitive and psychiatric outcomes in adulthood.

Genetic and Environmental Contributions to the Association Between Cannabis Use and Psychotic-Like Experiences in Young Adult Twins.

Nesvåg, Ragnar · 2017

This twin study of 2,793 young adults disentangled the genetic and environmental contributions to the cannabis-psychosis relationship. Cannabis use disorder symptoms were strongly associated with psychotic-like experiences, with an incidence rate ratio of 6.3.

Psychotic Symptoms in Attention-Deficit/Hyperactivity Disorder: An Analysis of the MTA Database.

Vitiello, Benedetto · 2017

Researchers followed 509 MTA study participants (childhood ADHD) and 276 age-matched controls for 16 years, assessing psychotic symptoms through young adulthood. ADHD did not increase the risk for psychotic symptoms.

Cannabis use in first episode psychosis: Meta-analysis of prevalence, and the time course of initiation and continued use.

Myles, Hannah · 2016

This meta-analysis pooled data from 37 studies to characterize the epidemiology of cannabis use in first-episode psychosis. Three key findings emerged.

Brain Imaging Studies on the Cognitive, Pharmacological and Neurobiological Effects of Cannabis in Humans: Evidence from Studies of Adult Users.

Weinstein, Aviv · 2016

This comprehensive review synthesized 103 structural and functional brain imaging studies of cannabis users published between 2000 and 2016, providing the most complete picture to date of how cannabis affects the human brain. Structural findings: Regular cannabis use was associated with volumetric and tissue changes, particularly in the hippocampus (memory) and amygdala (emotion).

Psychosocial sequelae of cannabis use and implications for policy: findings from the Christchurch Health and Development Study.

Fergusson, David M · 2015

The Christchurch Health and Development Study tracked 1,265 New Zealanders from birth to age 35, providing one of the most comprehensive longitudinal datasets on cannabis outcomes.

How cannabis causes paranoia: using the intravenous administration of ∆9-tetrahydrocannabinol (THC) to identify key cognitive mechanisms leading to paranoia.

Freeman, Daniel · 2015

This was the largest study of intravenous THC, randomizing 121 individuals with existing paranoid ideation to receive THC, placebo, or THC with prior cognitive awareness training.

Cannabidiol inhibits THC-elicited paranoid symptoms and hippocampal-dependent memory impairment.

Englund, Amir · 2013

In a between-subjects, double-blind design, 48 healthy participants received either 600 mg oral CBD (n=22) or placebo (n=26) before intravenous THC (1.5 mg).

The impact of cannabis use on cognitive functioning in patients with schizophrenia: a meta-analysis of existing findings and new data in a first-episode sample.

Yücel, Murat · 2012

In a surprising finding that contradicts common assumptions, the meta-analysis of 572 patients found that those with a history of cannabis use had superior neuropsychological functioning compared to non-using schizophrenia patients.

Cannabidiol enhances anandamide signaling and alleviates psychotic symptoms of schizophrenia.

Leweke, F Markus · 2012

PANSS total improvement: CBD 30.5 (±16.4) vs amisulpride 30.1 (±24.7), p=0.884.

Cannabis use and expression of mania in the general population.

Henquet, Cécile · 2006

Researchers followed 4,815 individuals aged 18-64 years in a longitudinal population-based study with assessments at baseline, one year, and three years.

Cannabis and the brain.

Iversen, Leslie · 2003

All known central effects of THC were mediated through CB1 receptors, with particularly high expression on GABAergic interneurons in the hippocampus, amygdala, and cerebral cortex.

Predicting the prognosis of primary and substance-associated psychoses using urine drug screens: A 5-year retrospective longitudinal study using medical records.

Aschenbrenner, Erich J · 2026

Cannabis alone at first psychosis presentation showed improved prognosis compared to negative drug screens but more chronic course than expected for substance-induced psychosis; cocaine showed the clearest substance-induced pattern with quick remission and low recurrence..

Differential effect of cannabis use and antipsychotic medication on extracellular free-water in the brain of individuals with early psychosis and controls.

Martínez-Sadurní, Laura · 2026

Past cannabis use was associated with lower extracellular free water (FW, an inflammation marker) in controls but elevated FW in people with recent-onset psychosis, particularly in temporal and parietal cortex.

Optimizing antipsychotic dosing for relapse prevention in cannabis-induced psychosis: A nationwide cohort study.

Mustonen, Antti · 2026

Using linked Swedish health registers, researchers identified all individuals with a first diagnosis of cannabis-induced psychosis and conducted a dose-response analysis of oral antipsychotic medications. The analysis modeled antipsychotic exposure as time-dependent across three dose categories (low: <0.6 DDD, moderate: 0.6–<1.4 DDD, high: ≥1.4 DDD) using within-individual comparisons — meaning each person served as their own control across different exposure periods. The primary outcome was hospitalization for any psychotic episode (schizophrenia-spectrum disorder or substance-induced psychosis).

Cannabis use and cardiometabolic risk in schizophrenia.

Paris, Jai · 2026

In 988 CATIE study participants with schizophrenia, THC-positive individuals (14.8%) had significantly lower metabolic syndrome prevalence (42.5% vs 60.5%, p < 0.001).

Gray Matter Volume Loss in Parkinson's Disease Psychosis and Cannabinoid Receptor Gene Expression in the Brain.

Pisani, Sara · 2026

There was a significant association between gray matter volume loss in Parkinson's disease psychosis and CB1 receptor gene expression across brain regions (r = 0.337, p < 0.001).

Substance abuse in first-episode psychosis at Chris Hani Baragwanath Hospital.

Shandu, Precious N · 2026

Substance use prevalence among first-episode psychosis patients was 73.6%.

Convergence of Cannabis and Psychosis on the Dopamine System.

Ahrens, Jessica · 2025

Cannabis use disorder (CUD) was associated with elevated neuromelanin-MRI signal in a set of ventral substantia nigra/ventral tegmental area voxels (387 of 2,060 voxels, corrected P=0.03).

The relationship between recreational cannabis use, psychotic-like experiences, and the salience network in adolescent and young adult twins.

Atmaca-Turan, Hande · 2025

Cannabis use was significantly associated with higher overall psychotic-like experience (PLE) frequency.

Investigating the polygenic relationship between heavy cannabis use and schizophrenia in the All of Us Research Program.

Austin-Zimmerman, Isabelle · 2025

The association between heavy cannabis use and schizophrenia has been documented for decades, but a fundamental question remains: does cannabis cause psychosis, does genetic vulnerability to psychosis drive cannabis use, or both? This study used polygenic scores — genetic risk calculators derived from large genome-wide association studies — to test these pathways in real individuals with data on both genetics and diagnoses. Using the All of Us Research Program (a diverse U.S.

Investigating the Polygenic Relationship Between Cannabis Use and Schizophrenia in the All of Us Research Program.

Austin-Zimmerman, Isabelle · 2025

Both cannabis use disorder and schizophrenia polygenic scores independently predicted schizophrenia diagnosis.

Adolescent cannabis use and onset of bipolar disorder: gaining causal clarity by viewing the evidence through the Bradford Hill lens.

Bartoli, Francesco · 2025

Evaluation of longitudinal studies using Bradford Hill criteria found the cannabis-bipolar disorder relationship shows a dose-response gradient, strong effect size, coherence, biological plausibility, and clear temporality.

The impact of socioeconomic factors on the incidence and characteristics of first-episode psychosis.

Belvederi Murri, Martino · 2025

Frequent cannabis use among teens (area-level) was associated with increased first-episode psychosis incidence (IRR=1.31).

Synaptic Density in Early Stages of Psychosis and Clinical High Risk.

Blasco, M Belen · 2025

Synaptic density (measured by SV2A binding) was significantly lower in first-episode psychosis and clinical high-risk participants compared to healthy controls.

Sociodemographic influences on substance use in psychosis in an African cohort.

Campbell, Megan L · 2025

Significant variations in cannabis consumption were observed across the four African countries studied.

Triple Burden of Cannabis Use, First Episode Psychosis and HIV in KwaZulu-Natal Province, South Africa.

Chhagan, Usha · 2025

Lifetime cannabis users scored higher on PANSS total, positive, disorganized, and excitement domains and lower on depression; HIV-positive cannabis users showed additional positive symptom elevation (p=0.023)..

The differential effects of medicinal cannabis on mental health: A systematic review.

de Bode, Nora · 2025

High doses of CBD provided some acute relief in anxiety disorders.

Methylomic signature of current cannabis use in two first-episode psychosis cohorts.

Dempster, Emma L · 2025

Current cannabis use was associated with differential methylation at a site in the CAVIN1 gene, independent of tobacco effects.

Cannabis-Associated Emergencies in the Emergency Department.

Eichhorn, David · 2025

In Canada after legalization, cannabis use among those 15+ rose from 15% to 25%, and hospital admissions doubled from 15 to 32 per 100,000.

Cognitive presentation at psychosis onset through premorbid deterioration and exposure to environmental risk factors.

Ferraro, Laura · 2025

Among 802 first-episode psychosis patients, those in the "deteriorating" cognitive cluster had higher cannabis exposure than the "intermediate" cluster with identical IQ, and all patient clusters had higher environmental risk scores than the 1,263 community controls..

Long-lasting behavioral, molecular and functional connectivity alterations after chronic THC exposure during adolescence in mice.

Gómez-Acero, Laura · 2025

Adolescent THC exposure impaired social interaction and increased vulnerability to sensorimotor gating deficiencies (similar to those in heavy cannabis users).

Association Between Cannabis Use and Neuropsychiatric Disorders: A Two-sample Mendelian Randomization Study.

Guo, Wei · 2025

Using two-sample Mendelian randomization with GWAS data, the study found genetically predicted lifetime cannabis use was associated with increased risk of Parkinson's disease (OR=1.78, 95% CI: 1.03-3.08) and ADHD in women (OR=1.65, 95% CI: 1.05-2.59).

Cannabis use and psychotic-like experiences in the All of Us Research Program.

Johnson, Emma C · 2025

Drawing from the All of Us Research Program—a massive, diverse U.S.

Changes in psychosis-related emergency department and hospitalization rates among youth following cannabis legalization in Colorado.

Joshi, Spruha · 2025

Monthly psychosis hospitalization rates for youth rose from 21.9 per 100,000 pre-medical expansion to 28.0 post-expansion and 32.3 post-recreational legalization.

Recent cannabis use affects the association between baseline immune markers and long-term outcomes in psychosis.

Kreis, Isabel · 2025

Only sTNFR1 independently predicted lower risk of psychiatric readmission and psychotic episodes over 10 years.

Stimulant and medicinal cannabis prescribing in patients referred to an early psychosis service in Queensland: A brief report.

McArdle, Peter · 2025

Before referral, 3.2% of patients were prescribed medicinal cannabis; after psychosis, this rose to 6.8%.

Influence of recent cannabis use on altered spectral entropy modulation and connectivity strength in patients with psychosis.

Molina, Vicente · 2025

Both cannabis-using and non-using psychosis patients showed impaired spectral entropy modulation and elevated connectivity strength compared to 86 healthy controls.

Hexahydrocannabinol (HHC) use and harms in Ireland: New findings from the 2024 European Web Survey on Drugs.

Mongan, Deirdre · 2025

Hexahydrocannabinol (HHC)—a semi-synthetic cannabinoid marketed as a legal alternative to cannabis—was openly sold in Irish shops until it was banned in July 2025.

The rising tide of drug-induced psychosis.

Murray, Robin M · 2025

Drug-induced psychosis from methamphetamine and cannabis has become more common over three decades.

Evidence of altered monoamine oxidase B, an astroglia marker, in early psychosis and high-risk state.

Nisha Aji, Kankana · 2025

Cannabis use had a significant effect on MAO-B availability (F=12.57, p=0.001, Cohen's f=0.57), with a significant group-by-cannabis interaction (p=0.03) showing lower MAO-B in cannabis-using clinical groups.

The Relationship of glutamate signaling to cannabis use and schizophrenia.

Niznikiewicz, Margaret · 2025

The review synthesizes three lines of evidence: cannabis is associated with psychosis in a subset of users, glutamate dysregulation is a feature of schizophrenia, and cannabis affects the glutamate system.

Cannabis and tobacco use in bipolar disorder: Associations with early onset, psychotic symptoms, and relapse risk (2015-2019).

Olivier, Luis · 2025

Cannabis was associated with earlier onset of bipolar disorder, current manic polarity, presence of psychotic symptoms, and higher likelihood of discontinuing treatment.

Cannabis and psychosis: minimising harm while maximising therapeutic potential.

Patel, Rashmi · 2025

Cannabis use increases the risk of psychosis, but cannabis-based medicinal products may provide additional therapeutic opportunities.

The Relationship Between Cannabis Use and Schizophrenia As a Risk Factor or For Its Therapeutic Potential: A Systematic Review of Evidence.

Rajput, Jaisingh · 2025

The cannabis-schizophrenia relationship is one of the most polarized debates in psychiatric research.

Self-disturbance in first-episode psychosis: Theoretical framework and potential cannabis interactions - a systematic review.

Ricci, Valerio · 2025

Among 3,847 participants across 22 studies, daily high-potency cannabis use was associated with 3.21-fold increased odds of clinically significant dissociation (95% CI 2.14-4.82) and more severe anomalous self-experiences.

Effects of persistent cannabis use on depression, psychosis, and suicidality following cannabis-induced psychosis: A longitudinal study.

Ricci, Valerio · 2025

Among 44 patients (22 cannabis users, 22 non-users) followed for 9 months after cannabis-induced FEP, continued cannabis users had persistently higher depression scores (p=0.0000001 at 9 months), suicidality (p<0.001), and PANSS positive scores (p<0.0002) compared to those who stopped.

Cannabis use and psychotic-like experiences: A systematic review of biological vulnerability, potency effects, and clinical trajectories.

Ricci, Valerio · 2025

Across 38 studies, four major risk factor categories emerged for psychotic-like experiences (PLEs) in non-clinical populations: biological vulnerabilities (metabolic profiles, genetics, neurobiology), substance use patterns (especially high-potency cannabis), socio-demographic factors (digital media, ethnic density, gender), and downstream consequences (suicidal behavior, cognitive impairment).

Polygenic and Polyenvironment Interplay in Schizophrenia-Spectrum Disorder and Affective Psychosis; the EUGEI First Episode Study.

Rodriguez, Victoria · 2025

In 573 first-episode psychosis cases and 1,005 controls, polygenic risk for schizophrenia was the strongest genetic predictor of schizophrenia-spectrum disorders, with a notably larger effect in people not exposed to strong environmental risks like frequent cannabis use (OR 2.43 unexposed vs 1.35 exposed).

The Complex Relationship Between Cannabis Use and Mental Health: Considering the Influence of Cannabis Use Patterns and Individual Factors.

Sagar, Kelly A · 2025

This review highlights that seemingly contradictory findings in cannabis-mental health research are largely explained by unmeasured variables.

Correlates and trajectories of alcohol and cannabis misuse in the early phase of psychosis: Do we need substance specific interventions?

Spanevello, Carolina · 2025

Alcohol users tended to maintain consumption over time, while some cannabis users reduced their use.

The impact of childhood trauma and cannabis use on paranoia: a structural equation model approach.

Trotta, Giulia · 2025

Cannabis use alone was not significantly associated with paranoia (p=0.18).

Cluster profiles of distressing psychotic-like experiences among children and associations with genetic risk, prenatal cannabis exposure, and social-environmental characteristics.

Yuan, Qingyue · 2025

Three distressing PLE subgroups were identified: hallucinatory-like, paranoid-like, and multiple domains.

Altered neurobehavioral reward response predicts psychotic-like experiences in youth exposed to cannabis prenatally.

Amir, Carolyn M · 2024

Prenatal cannabis exposure (PCE) was longitudinally associated with psychotic-like experiences in youth.

The Role of Social Deprivation and Cannabis Use in Explaining Variation in the Incidence of Psychotic Disorders: Findings From the EU-GEI Study.

Brink, Vera · 2024

Lower owner-occupancy was independently associated with increased first-episode psychosis incidence (aIRR: 0.76) and non-affective psychosis (aIRR: 0.68).

Real world clinical outcomes of treatment of cannabis-induced psychosis and prevalence of cannabis-related primary psychosis: a retrospective study.

Chuenchom, Onrumpha · 2024

All patients presented with psychosis; 64% had mood symptoms and 61% sleep problems.

Biobehavioral Interactions between Endocannabinoid and Hypothalamicpituitary- adrenal Systems in Psychosis: A Systematic Review.

Colizzi, Marco · 2024

Both systems show independent contributions to psychosis risk, but they also interact bidirectionally: cannabis use affects endocannabinoid tone, stress exposure alters the HPA axis, and crucially, THC also affects the HPA axis while childhood trauma affects endocannabinoid signaling, revealing cross-system perturbation..

Cannabis use influences disorganized symptoms severity but not transition in a cohort of non-help-seeking individuals at-risk for psychosis from São Paulo, Brazil.

de Medeiros, Matheus Wanderley · 2024

In a community sample of 109 at-risk individuals and 197 controls from Sao Paulo, Brazil, cannabis use patterns did not differ between the two groups and did not predict transition to psychiatric disorders.

DNA methylation at cannabinoid type 1 and dopamine D2 receptor genes in saliva samples of psychotic subjects: Is there an effect of Cannabis use?

Di Bartolomeo, Martina · 2024

DNA methylation at CNR1 and DRD2 genes was significantly higher in psychotic subjects than healthy controls, and the two genes' methylation levels were directly correlated.

Predictors of relapse and engagement in care one year after ending services in an urban safety net coordinated specialty care program for first episode psychosis.

Hyatt, Andrew · 2024

Cannabis use at last program contact was associated with a fourfold higher risk of relapse (aOR 4.06, 95% CI 1.56-10.56) and significantly lower rates of outpatient psychiatric follow-up (aOR 0.32, 95% CI 0.12-0.94) in the 12 months after ending coordinated specialty care.

Using Task-fMRI to Explore the Relationship Between Lifetime Cannabis Use and Cognitive Control in Individuals With First-Episode Schizophrenia.

Lesh, Tyler A · 2024

First-episode schizophrenia patients with cannabis history (FES+CAN, n=48) showed higher cognitive control performance and higher dorsolateral prefrontal cortex (DLPFC) activation during task-based fMRI compared to patients without cannabis history (FES-CAN, n=28).

Regulatory Landscape of Cannabis Warning Labels in US States with Legal Retail Nonmedical Cannabis, 2024.

Meek, Caroline J · 2024

Among 20 states with legal retail cannabis, only 2 required mental health risk warnings and 2 required high-potency psychosis warnings.

Clinical and public safety risks associated with cannabis legalization and frequency of cannabis use among forensic mental health patients.

Penney, Stephanie R · 2024

One-third of forensic patients used cannabis over the study period, with frequency increasing significantly after legalization.

Changes in Cannabis Use Patterns in Psychiatric Populations Pre- and Post-Legalization of Recreational Cannabis Use in Canada: A Repeated Cross-Sectional Survey.

Sorkhou, Maryam · 2024

The odds of daily/near-daily cannabis use increased nine-fold (aOR=9.19) among people with schizophrenia between pre-legalization (2018) and two years post (2020).

The Role of Cannabis in the Development of Psychosis.

Türkoğlu, Özge · 2024

Earlier age of cannabis use onset, genetic predisposition, and heavy/high-potency use all independently increase psychosis risk.

Does a history of cannabis use influence onset and course of schizophrenia?

Allebeck, Peter · 2023

Among 160 patients with validated schizophrenia, the 32 with a cannabis history had earlier age at onset, higher number of hospital admissions, and higher total hospital days compared to the 128 without.

Neurobehavioral risk factors influence prevalence and severity of hazardous substance use in youth at genetic and clinical high risk for psychosis.

Amir, Carolyn M · 2023

CHR-P youth had significantly higher substance use across tobacco, alcohol, and cannabis compared to controls, while 22qDel carriers had significantly lower use.

Influence of cannabis use on incidence of psychosis in people at clinical high risk.

Chester, Lucy A · 2023

Among 334 clinical high-risk individuals followed for 2 years, 16.2% developed psychosis.

The therapeutic potential of purified cannabidiol.

O'Sullivan, Saoirse Elizabeth · 2023

The areas with the most clinical evidence for purified CBD were anxiety (7 uncontrolled + 17 RCTs), psychosis/schizophrenia (1 uncontrolled + 8 RCTs), PTSD (2 uncontrolled + 4 RCTs), and substance abuse (2 uncontrolled + 3 RCTs).

Scoping Review of Cannabis-Reduction Psychosocial Interventions and Reasons for Use among Young Adults with Psychosis.

Petros, Ryan · 2023

Young adults with psychosis use cannabis for pleasure, to reduce dysphoria, and for social reasons.

CANNABIS USE AND SUICIDE IN NON-AFFECTIVE PSYCHOSIS: A MINI-REVIEW OF RECENT LITERATURE.

Ricci, Valerio · 2023

Three cohort studies agreed that cannabis use was associated with increased suicide risk in schizophrenia patients.

Aberrant salience in cannabis-induced psychosis: a comparative study.

Ricci, Valerio · 2023

SPICE users had more severe and persistent positive symptoms than THC users and non-users.

First episode psychosis with and without the use of cannabis and synthetic cannabinoids: Psychopathology, global functioning and suicidal ideation and antipsychotic effectiveness.

Ricci, Valerio · 2023

THC users and especially SPICE users displayed more severe positive symptoms than non-users.

Predictive impact of different acute cannabis intoxication effects with regard to abstinence motivation and cessation of use.

Schnell, Thomas · 2023

Paranoid/dysphoric intoxication effects were the strongest predictors of abstinence motivation.

Exploration of cannabis use and polygenic risk scores on the psychotic symptom progression of a FEP cohort.

Segura, Alex G · 2023

Current cannabis use was associated with increased positive symptoms.

The association between reasons for first using cannabis, later pattern of use, and risk of first-episode psychosis: the EU-GEI case-control study.

Spinazzola, Edoardo · 2023

Starting cannabis use "to feel better/cope" was associated with higher odds of first-episode psychosis (FEP) compared to starting "because of friends." Path analysis showed reasons for first use influenced later patterns (frequency, potency, duration) which in turn affected psychosis risk..

Nondisordered Cannabis Use Among US Adolescents.

Sultan, Ryan S · 2023

Nondisordered cannabis use (NDCU) was 4 times more prevalent than cannabis use disorder (10.2% vs.

Cannabis use as a potential mediator between childhood adversity and first-episode psychosis: results from the EU-GEI case-control study.

Trotta, Giulia · 2023

Cannabis use acted as a partial mediator between childhood adversity and first-episode psychosis.

Cannabis and Psychosis.

West, Michelle L · 2023

Cannabis use is associated with increased risk of psychotic symptoms (both subthreshold and full), exacerbation of psychosis in vulnerable youth, and worse outcomes in established psychotic disorders.

Relationship between patterns of cannabis use and functional and symptomatic trajectories in first-episode psychosis.

Wright, Abigail C · 2023

Cannabis use patterns were characterized among FEP patients, and continued use was associated with worse symptomatic and functional outcomes.

Early versus late risk factors for deficit and nondeficit schizophrenia.

Alabaf, Setareh · 2022

Deficit schizophrenia patients had significantly lower cannabis use at first psychotic episode (p=0.005), less physical/sexual abuse (p=0.033), and less crime-related trauma (p=0.012).

Is the effect of cognitive reserve in longitudinal outcomes in first-episode psychoses dependent on the use of cannabis?

Amoretti, Silvia · 2022

Cognitive reserve was associated with better cognitive performance regardless of cannabis use.

Clinical practice guideline on pharmacological and psychological management of adult patients with schizophrenia spectrum disorders and a comorbid substance use.

Arranz, Belen · 2022

For schizophrenia with cannabis use: no antipsychotic (olanzapine, risperidone, haloperidol, or clozapine) could be recommended over another (weak recommendation).

Anandamide Hydrolysis Inhibition Reverses the Long-Term Behavioral and Gene Expression Alterations Induced by MK-801 in Male Rats: Differential CB1 and CB2 Receptor-Mediated Effects.

Bauminger, Hagar · 2022

The anandamide hydrolysis inhibitor URB597, given in late adolescence, reversed both novel object recognition deficits (via CB2 receptors) and social interaction abnormalities (via CB1 receptors) induced by early-adolescence MK-801 administration, while also normalizing glutamate and GABA marker expression in the prefrontal cortex..

Clinical and treatment predictors of relapse during a three-year follow-up of a cohort of first episodes of schizophrenia.

Bioque, Miquel · 2022

Cannabis consumption was dramatically higher among those who relapsed (93.2%) compared to those who maintained remission (56.7%, p<0.001).

Cannabidiol (CBD) as a novel treatment in the early phases of psychosis.

Chesney, Edward · 2022

CBD has demonstrated antipsychotic effects in clinical studies and has a relatively benign side effect profile compared to standard antipsychotics.

Latent inhibition, aberrant salience, and schizotypy traits in cannabis users.

Dawes, Christopher · 2022

Current cannabis use was associated with higher "disorganized" and "cognitive-perceptual" schizotypy scores and higher aberrant salience inventory scores.

The association between cannabis use and facial emotion recognition in schizophrenia, siblings, and healthy controls: Results from the EUGEI study.

Fusar-Poli, Laura · 2022

Better facial emotion recognition was associated with lifetime regular cannabis use across all three groups: schizophrenia patients (B=1.36), siblings (B=2.17), and healthy controls (B=3.10).

Incidence of inpatient cases with mental disorders due to use of cannabinoids in Germany: a nationwide evaluation.

Gahr, Maximilian · 2022

All categories of cannabinoid-related psychiatric hospitalizations increased significantly: intoxications, harmful use, dependence syndrome, withdrawal, psychotic disorders, and residual/late-onset psychotic disorders.

Surface-based brain morphometry in schizophrenia vs. cannabis-induced psychosis: A controlled comparison.

Ghosh, Abhishek · 2022

Schizophrenia with heavy cannabis use (SZC) showed the lowest cortical thickness, depth, and gyrification, followed by cannabis-induced psychosis (CIP), then healthy controls.

Lifetime Cannabis Use Is Not Associated With Negative Beliefs About Medication in Patients With First Treatment Psychosis.

Gjerde, Priyanthi B · 2022

Neither lifetime cannabis use, current use, nor cannabis abuse diagnosis was associated with negative beliefs about medicines as measured by the BMQ questionnaire.

Acute effects of Δ9-tetrahydrocannabinol and cannabidiol on auditory mismatch negativity.

Greenwood, Lisa-Marie · 2022

THC and CBD both increased duration and intensity MMN amplitude in less-frequent users.

Cannabinoids, reward processing, and psychosis.

Gunasekera, Brandon · 2022

THC modulated activity in the striatum, midbrain, insula, and anterior cingulate during reward processing, with some effects correlating with the severity of THC-induced psychotic symptoms.

Cannabis use selectively modulates circulating biomarkers in the blood of schizophrenia patients.

Ibarra-Lecue, Inés · 2022

Platelet serotonin 2A receptors, active Akt protein, anandamide, other lipid mediators, and pro-inflammatory IL-6 were all significantly increased in schizophrenia patients.

Cannabis Vapor Exposure Alters Neural Circuit Oscillatory Activity in a Neurodevelopmental Model of Schizophrenia: Exploring the Differential Impact of Cannabis Constituents.

Jenkins, Bryan W · 2022

NVHL rats (schizophrenia model) had reduced baseline gamma power in multiple brain regions.

Effects of cannabidiol on vacuous chewing movements, plasma glucose and oxidative stress indices in rats administered high dose risperidone.

Kajero, Jaiyeola Abiola · 2022

CBD (5 mg/kg) significantly reduced risperidone-induced elevated fasting blood sugar when given after risperidone.

Predictors of admission to an assertive outreach service for psychosis in Lebanon.

Kassir, Ghida · 2022

Cannabis use disorder was a significant predictor of enrollment in the Psychosis Recovery Outreach Program (OR 2.83, 95% CI 1.25-6.37).

A scoping review of the use of cannabidiol in psychiatric disorders.

Kirkland, Anna E · 2022

Only 16 randomized controlled trials or within-subject studies met inclusion criteria.

A Cannabinoid Hypothesis of Schizophrenia: Pathways to Psychosis.

Little, Rachel · 2022

The review describes several putative pathways from cannabis to psychosis, integrating evidence about the endocannabinoid system, THC's effects on dopamine and glutamate signaling, and the connection between cannabis use and first-episode psychosis..

Handedness as a neurodevelopmental marker in schizophrenia: Results from the FACE-SZ cohort.

Mallet, Jasmina · 2022

Among 667 schizophrenia patients, 42.4% were non-right-handed and 34.1% mixed-handed.

Atypical Antipsychotic Drugs in Dual Disorders: Current Evidence for Clinical Practice.

Martinotti, Giovanni · 2022

Across 41 studies, most dual diagnosis patients were male with schizophrenia, and cannabis was the most abused substance followed by alcohol.

Prevalence of cannabis use in people with psychosis in KwaZulu-Natal, South Africa.

Mona, Khanya · 2022

Current cannabis use was 48.9% and lifetime use 51.1%.

Geographical variation in hospitalization for psychosis associated with cannabis use and cannabis legalization in the United States: Submit to: Psychiatry Research.

Moran, Lauren V · 2022

There were an estimated 129,070 hospital discharges for psychosis associated with cannabis in 2017.

The Link Between Cannabis Use and Violent Behavior in the Early Phase of Psychosis: The Potential Role of Impulsivity.

Moulin, Valerie · 2022

Cannabis use is particularly high in early-phase psychosis (EPP) and is a confirmed risk factor for violent behavior in this population.

Pattern of predictive features of continued cannabis use in patients with recent-onset psychosis and clinical high-risk for psychosis.

Penzel, Nora · 2022

Clinical interview data alone predicted continued cannabis use with 73% accuracy in 109 recent-onset psychosis patients.

Cannabis exposure during adolescence: A uniquely sensitive period for neurobiological effects.

Peters, K Z · 2022

The endocannabinoid system changes during adolescence affect how it modulates developing dopamine circuits.

Gender Differences in Dual Diagnoses Associated with Cannabis Use: A Review.

Prieto-Arenas, Laura · 2022

Studies consistently show gender differences in cannabis-associated psychiatric symptoms, but the direction varies across studies and conditions.

Contingency Management for Treatment of Cannabis Use Disorder in Co-Occurring Mental Health Disorders: A Systematic Review.

Rodas, Justyne D · 2022

Contingency management produced cannabis use reductions and periods of abstinence in individuals with psychotic-spectrum disorders or major depressive disorder.

The associations of cannabis and methamphetamine use with cognitive performance over the first 2 years of treatment in schizophrenia spectrum disorders.

Scheffler, Freda · 2022

In 81 patients with first-episode schizophrenia spectrum disorders treated over 24 months, positive methamphetamine tests predicted less cognitive improvement, but positive cannabis tests did not..

Does cannabis use predict aggressive or violent behavior in psychiatric populations? A systematic review.

Sorkhou, Maryam · 2022

Cross-sectional associations between cannabis use and aggression/violence were found in PTSD samples.

Psychotomimetic symptoms after a moderate dose of a synthetic cannabinoid (JWH-018): implications for psychosis.

Theunissen, Eef L · 2022

JWH-018 (average dose 5.52 mg) caused psychedelic effects (altered internal and external perception), dissociative effects (amnesia, derealization, depersonalization), and confusion in healthy participants with no history of mental illness..

Cannabis use is associated with lower retention in methadone maintenance treatment, but not among schizophrenic- and other chronically psychotic patients.

Volkov, Ilan · 2022

Cannabis-using methadone patients had significantly shorter cumulative retention (6.0 years) than non-users (9.1 years).

Impact of cannabis legalization on healthcare utilization for psychosis and schizophrenia in Colorado.

Wang, George Sam · 2022

As recreational dispensaries per 10,000 residents increased, psychosis ED visits increased 24% (IRR 1.24, 95% CI 1.02-1.49) while schizophrenia ED visits showed no significant change (IRR 0.95).

Premorbid characteristics of patients with DSM-IV psychotic disorders.

Widing, Line · 2022

17.5% of PNOS participants and 11.5% of schizophrenia spectrum participants used cannabis before age 16, compared to only 5.3% of psychotic bipolar participants.

Catatonic Episodes Related to Substance Use: A Cross-Sectional Study Using Electronic Healthcare Records.

Yeoh, Su Ying · 2022

Of 108 substance-related catatonic episodes, cannabis was linked to 31 of 54 intoxication-related episodes and 37 of 50 chronic use-related episodes.

The Impact of THC and CBD in Schizophrenia: A Systematic Review.

Ahmed, Saeed · 2021

Intravenous THC increased psychosis in stable patients.

Lifetime Cannabis Use Disorder Is Not Associated With Lifetime Impulsive Behavior and Severe Violence in Patients With Schizophrenia Spectrum Disorders From a High-Security Hospital.

Comai, Stefano · 2021

Violent and nonviolent psychotic patients had similar rates of cannabis use disorder.

The independent and combined effects of cannabis use and systemic inflammation during the early stages of psychosis: exploring the two-hit hypothesis.

Corsi-Zuelli, Fabiana · 2021

Cannabis did not increase inflammation (ruling out a mediating pathway).

Are psychotic-like experiences related to a discontinuation of cannabis consumption in young adults?

Daedelow, Laura S · 2021

Mean cannabis use increased from age 19 to 22.

Cannabis Use, Schizotypy and Kamin Blocking Performance.

Dawes, Christopher · 2021

Neither lifetime nor current cannabis use was associated with changes in Kamin blocking scores.

Are Schizophrenic disorders with or without early cannabis use neurobiologically distinct disease entities? A meta-analysis of magnetic resonance imaging studies.

De Peri, Luca · 2021

Both schizophrenia patients with cannabis use (n=227) and without (n=238) showed reduced whole brain, total grey matter, and hippocampal volumes compared to healthy controls (n=366).

Differential effects of cannabis exposure during early versus later adolescence on the expression of psychosis in homeless and precariously housed adults.

Gicas, Kristina M · 2021

Early cannabis exposure (by age 15) was associated with increased risk of substance-induced psychosis (OR=1.09, p<0.05).

Impact of previous tobacco use with or without cannabis on first psychotic experiences in patients with first-episode psychosis.

González-Blanco, Leticia · 2021

FEP patients with prior tobacco-only use (n=56) had more sleep disturbances (42.9% vs.

The Yin and Yang of Cannabis: A Systematic Review of Human Neuroimaging Evidence of the Differential Effects of Δ9-Tetrahydrocannabinol and Cannabidiol.

Gunasekera, Brandon · 2021

Despite heterogeneous methods, an overall pattern of opposite THC and CBD effects was evident, primarily from head-to-head challenge studies.

The Relationship between Alcohol-Cannabis Use and Stressful Events with the Development of Incident Clinical Psychosis in a Community-Based Prospective Cohort.

Kirli, Umut · 2021

Heavy alcohol drinking and cannabis use during follow-up each independently predicted incident clinical psychosis.

Adversity in childhood/adolescence and premorbid tobacco, alcohol, and cannabis use among first-episode psychosis patients.

Langlois, Stephanie · 2021

Violence and Environmental Adversity (a factor combining community violence, housing instability, and other environmental stressors) was significantly associated with 5 of 6 substance use variables.

Experimentally exploring the potential behavioral effects of personalized genetic information about marijuana and schizophrenia risk.

Lebowitz, Matthew S · 2021

Participants told they had a genetic predisposition for marijuana to increase schizophrenia risk rated the likelihood and importance of avoiding marijuana as significantly higher than controls.

Acute effects of cannabis on speech illusions and psychotic-like symptoms: two studies testing the moderating effects of cannabidiol and adolescence.

Mokrysz, Claire · 2021

Cannabis increased psychotic-like symptoms (PSI scores) in both studies.

Cannabis use among early adolescents and transdiagnostic mental health risk factors.

Moreno-Mansilla, Sara · 2021

Cannabis users scored significantly higher on anomalous reality perception (d = 0.60), hopelessness (d = 0.85), depression symptoms (d = 0.80), rumination (d = 0.48), and anxiety (d = 0.39).

Association between age of cannabis initiation and gray matter covariance networks in recent onset psychosis.

Penzel, Nora · 2021

Earlier cannabis initiation was linked to greater cerebellar gray matter volume in a network previously identified as altered in schizophrenia, independent of confounders.

Symptomatology and neurocognition among first-episode psychosis patients with and without cannabis use in the three months prior to first hospitalization.

Pope, Leah G · 2021

Cannabis users had significantly lower anhedonia-asociality scores (10.7 vs 12.1, p=0.023) but more severe delusions (19.3 vs 15.9, p=0.005) and bizarre behavior (p=0.01).

Cannabis-induced psychosis: clinical characteristics and its differentiation from schizophrenia with and without cannabis use.

Rentero, David · 2021

Cannabis-induced psychosis (CIP) patients had lower negative PANSS scores (12.9 vs 17.2, p<0.001), fewer auditory hallucinations (60.3% vs 78.9%), and more mania (26.1% vs 12.3%, p<0.001) compared to schizophrenia with cannabis.

Cannabis use disorder and dissociation: A report from a prospective first-episode psychosis study.

Ricci, V · 2021

Cannabis-using FEP patients showed higher positive symptoms, higher dissociative experiences (DES-II), and worse functioning (GAF) than non-users at onset.

Opposite Roles for Cannabidiol and δ-9-Tetrahydrocannabinol in Psychotomimetic Effects of Cannabis Extracts: A Naturalistic Controlled Study.

Sainz-Cort, Alberto · 2021

THC+CBD combined extracts produced significantly lower psychotomimetic scores than THC alone.

Cannabis use and clinical outcome in people with first-episode schizophrenia spectrum disorders over 24 months of treatment.

Scheffler, Freda · 2021

Among 98 first-episode schizophrenia patients treated with long-acting injectable antipsychotic, cannabis users (n=45) and non-users (n=53) had similar trajectories in symptom reduction and remission rates over 24 months, but more frequent cannabis use (measured by urine testing) predicted relapse..

Impact of cannabis use on outcomes of patients admitted to an involuntary psychiatric unit: A retrospective cohort study.

Soler, Stephan · 2021

Of 370 involuntarily admitted psychiatric patients, 130 tested THC-positive.

Cannabis use and metabolic syndrome among clients with first episode psychosis.

Stiles, Erik · 2021

In the RAISE-ETP program (n=404), cannabis users had similar baseline metabolic syndrome rates as abstainers but showed lower triglycerides, elevated HDL, and were less likely to develop metabolic syndrome over the study period..

Relationship between cannabis use and psychotic experiences in college students.

Wright, Abigail C · 2021

Greater weekly cannabis use was associated with increased hallucinatory experiences (persisting after controlling for depression) and delusional ideation (not persisting after depression adjustment).

Comparison between a morocco and a native-born population, in a sample of first episode psychosis.

Arranz, Sara · 2020

Moroccan patients (28.9% of sample) were more likely to be male, had fewer years of education, and lower functionality scores.

Understanding sex differences in long-term outcomes after a first episode of psychosis.

Ayesa-Arriola, Rosa · 2020

At first contact, women were older at onset, had higher premorbid adjustment and IQ, were more often employed and living independently.

Cannabinoids and psychotic symptoms: A potential role for a genetic variant in the P2X purinoceptor 7 (P2RX7) gene.

Boks, Marco P · 2020

A SNP in the P2RX7 gene (rs7958311) was associated with increased psychotic-like experiences in regular cannabis users (p = 1.10 x 10^-7) and was replicated in the IMAGEN cohort (p = 0.020).

Evidence of Slow Neural Processing, Developmental Differences and Sensitivity to Cannabis Effects in a Sample at Clinical High Risk for Psychosis From the NAPLS Consortium Assessed With the Human Startle Paradigm.

Cadenhead, Kristin S · 2020

CHR participants who converted to psychosis had significantly slower startle latency than non-converters, driven by female participants.

Characterizing psychosis-relevant phenomena and cognitive function in a unique population with isolated, chronic and very heavy cannabis exposure.

D'Souza, Deepak Cyril · 2020

Cases averaged 30,000+ lifetime cannabis exposures with no other substance use.

Do the effects of cannabis on the hippocampus and striatum increase risk for psychosis?

Daniju, Y · 2020

Using the MAM rodent model as a framework, the review found clear evidence that cannabis/cannabinoids affect hippocampal and medial temporal lobe function and structure.

Adolescent cannabinoid exposure interacts with other risk factors in schizophrenia: A review of the evidence from animal models.

Dunn, Ariel L · 2020

When adolescent cannabinoid exposure was combined with early-life adversity in animal models, patterns of synergistic and protective effects emerged.

Moderating role of cannabis use between insight and depression in early psychosis.

Elowe, Julien · 2020

A three-way interaction between cannabis use, insight, and medication adherence predicted depression levels one year post-diagnosis.

Predictors of psychosis breakthrough during 24 months of long-acting antipsychotic maintenance treatment in first episode schizophrenia.

Emsley, Robin · 2020

About 21% of patients developed breakthrough psychotic symptoms despite assured medication adherence via long-acting injections.

Cannabidiol for the treatment of psychosis among patients with schizophrenia and other primary psychotic disorders: A systematic review with a risk of bias assessment.

Ghabrash, Maykel Farag · 2020

CBD showed limited antipsychotic efficacy across studies, with no evidence supporting cognitive or functional benefits.

Cannabinoid use in psychotic patients impacts inflammatory levels and their association with psychosis severity.

Gibson, Claire L · 2020

While PANSS psychosis scores were similar between groups, cannabinoid-positive patients showed a negative correlation between IL-6 levels and psychosis severity, meaning higher inflammation was associated with lower symptom scores.

Psychotic disorders hospitalizations associated with cannabis abuse or dependence: A nationwide big data analysis.

Gonçalves-Pinho, Manuel · 2020

Cannabis-related psychotic disorder hospitalizations rose 29.4 times over 15 years.

Predicting factors for non-suicidal self-injury in patients with schizophrenia spectrum disorders and the role of substance use.

Güney, Erengül · 2020

Substance use disorder increased NSSI risk approximately 4-fold.

Associations of substance use, psychosis, and mortality among people living in precarious housing or homelessness: A longitudinal, community-based study in Vancouver, Canada.

Jones, Andrea A · 2020

Over 10 years of follow-up, participants with co-occurring substance use and psychotic disorders had higher mortality rates than those with either condition alone.

Dosage, Efficacy and Safety of Cannabidiol Administration in Adults: A Systematic Review of Human Trials.

Larsen, Christian · 2020

Across 25 studies (927 patients), CBD showed anxiolytic effects with acute administration and therapeutic effects for social anxiety disorder, psychotic disorder, and substance use disorders.

Persistent cannabis use among young adults with early psychosis receiving coordinated specialty care in the United States.

Marino, Leslie · 2020

Of 938 first-episode psychosis patients in Coordinated Specialty Care, 38.8% used cannabis at admission and 32.8% had persistent use at 1 year.

Early onset of cannabis use and violent behavior in psychosis.

Moulin, Valerie · 2020

In a 36-month prospective cohort of 265 early psychosis patients, violent patients began cannabis use at an average age of 15.3 vs.

Does cannabis use predict psychometric schizotypy via aberrant salience?

O'Tuathaigh, Colm M P · 2020

Among 910 students, frequent cannabis use predicted higher scores on positive and disorganized schizotypy subscales.

The Association Between Cannabis Use and Schizophrenia: Causative or Curative? A Systematic Review.

Patel, Shweta · 2020

After screening 96 articles and including 12 final studies (5 traditional reviews, 2 systematic reviews, 2 meta-analyses, 3 observational), 10 studies supported a causative link between cannabis and schizophrenia, 8 supported symptom exacerbation, and 6 supported therapeutic effects of CBD.

Co-occurrence across time and space of drug- and cannabinoid- exposure and adverse mental health outcomes in the National Survey of Drug Use and Health: combined geotemporospatial and causal inference analysis.

Reece, Albert Stuart · 2020

Across 410,138 NSDUH respondents (76.7% response rate), cannabis exposure was significantly associated with any mental illness, major depression, serious mental illness (SMI), and suicidal ideation in geospatial models adjusted for demographics and other substance use.

Medicinal cannabis for psychiatric disorders: a clinically-focused systematic review.

Sarris, Jerome · 2020

CBD showed tentative support for reducing social anxiety.

Individuals with psychosis and a lifetime history of cannabis use show greater deficits in emotional experience compared to non-using peers.

Schnakenberg Martin, Ashley M · 2020

Compared to non-using schizophrenia patients (n=36), those with lifetime cannabis use (n=35) expressed less ability to express emotions, were less likely to anticipate pleasure, and had poorer social functioning.

Cannabidiol as a treatment option for schizophrenia: recent evidence and current studies.

Schoevers, Julie · 2020

Recent trials focused on sub-acute schizophrenia, clinical high-risk for psychosis (CHR-P), and frequent cannabis users.

Cannabis Use Is Associated With Increased Levels of Soluble gp130 in Schizophrenia but Not in Bipolar Disorder.

Szabo, Attila · 2020

Screening 13 plasma inflammatory markers, cannabis users in the schizophrenia group had significantly elevated soluble gp130 (sgp130) compared to non-users (p=0.002, surviving multiple testing correction).

The prevalence and clinical correlates of substance use disorders in patients with psychotic disorders from an Upper-Middle-Income Country.

Temmingh, Henk S · 2020

Among 248 patients with psychotic disorders, cannabis use disorders (34.3%) were the most prevalent, followed by alcohol (30.6%) and methamphetamine (27.4%).

Cannabis use influence on peripheral brain-derived neurotrophic factor levels in antipsychotic-naïve first-episode psychosis.

Toll, A · 2020

Among 70 drug-naive first-episode psychosis patients and 57 healthy volunteers, cannabis use was associated with reduced BDNF levels only in the psychosis group.

Exploring Phenotypic and Genetic Overlap Between Cannabis Use and Schizotypy.

Vaissiere, James · 2020

Positive phenotypic correlations (range 0.05-0.18) were found between 11 of 12 cannabis use and schizotypy trait pairs in UK Biobank.

Imaging Brain Fatty Acid Amide Hydrolase in Untreated Patients With Psychosis.

Watts, Jeremy J · 2020

FAAH did not differ significantly between 27 patients with psychotic disorders and 36 healthy controls.

Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus.

Yu, Tao · 2020

Psychotic-like experiences were associated with reduced expansion of the right uncus between ages 14 and 19 (p=0.002).

Review of the many faces of synthetic cannabinoid toxicities.

Alipour, Azita · 2019

Synthetic cannabinoids produced a wide range of severe toxicities including arrhythmias, myocardial infarction, sudden cardiac death, psychosis, suicidal ideation, seizures, acute tubular necrosis, and intracranial hemorrhage.

Neuropsychiatric Sequelae in Adolescents With Acute Synthetic Cannabinoid Toxicity.

Anderson, Sarah Ann R · 2019

Synthetic cannabinoid-only exposure (n=107) was associated with 3.4x higher odds of coma/CNS depression (OR 3.42, 95% CI 1.51-7.75) and 3.9x higher odds of seizures (OR 3.89, 95% CI 1.39-10.94) compared to cannabis-only exposure (n=86).

Association of smoked cannabis with treatment resistance in schizophrenia.

Arsalan, Arsalan · 2019

The treatment resistance rate was over 60% in this cohort.

Gene-environment interaction between an endocannabinoid system genetic polymorphism and cannabis use in first episode of psychosis.

Bioque, Miquel · 2019

The FAAH rs2295633 genetic polymorphism interacted with cannabis use to dramatically increase psychosis risk.

The neuropsychological profiles of young psychosis patients with and without current cannabis use.

Bogaty, Sophia E R · 2019

Healthy controls outperformed both patient groups across most cognitive measures, but no significant differences were found between cannabis-using (n=24) and cannabis-abstinent (n=79) psychosis patients on any cognitive measure, including premorbid intelligence, processing speed, flexibility, memory, attention, and visuospatial function..

Cannabis and Neuropsychiatric Disorders: An Updated Review.

Chayasirisobhon, Sirichai · 2019

CBD has demonstrated therapeutic benefit across multiple neuropsychiatric conditions including autism spectrum disorder, anxiety, psychosis, neuropathic pain, cancer pain, migraine, MS, Alzheimer disease, Parkinson disease, Huntington disease, hypoxic-ischemic injury, and epilepsy.

Cannabis-related emergencies in children and teens.

Chen, Yih-Chieh · 2019

Cannabis-related pediatric ED visits are rising with changing legislation.

Positive and Negative Effects of Cannabis and Cannabinoids on Health.

Cohen, Koby · 2019

Repeated cannabis use is associated with respiratory and cardiovascular disorders, cognitive alterations, psychosis, schizophrenia, and mood disorders.

Modulatory effects of cannabinoids on brain neurotransmission.

Cohen, Koby · 2019

CB1 and CB2 receptors interact with six major neurotransmitter systems: dopamine, serotonin, noradrenaline, GABA, glutamate, and opioids.

Descriptive Psychopathology of the Acute Effects of Intravenous Delta-9-Tetrahydrocannabinol Administration in Humans.

Colizzi, Marco · 2019

In the 20 minutes after THC, 94% experienced at least mild symptoms (19% moderate-severe).

Cannabis acute use impacts symptoms and functionality in a cohort of antipsychotic naïve First Episode of Psychosis individuals.

Coutinho, Luccas S · 2019

Acute cannabis users had higher excitement symptoms and worse functioning at baseline.

Cannabidiol as a potential treatment for psychosis.

Davies, Cathy · 2019

CBD shows potential as a novel antipsychotic with a unique non-dopamine-D2 mechanism of action.

Hospital Stay in Synthetic Cannabinoid Users With Bipolar Disorder, Schizophrenia, or Other Psychotic Disorders Compared With Cannabis Users.

Deng, Huiqiong · 2019

Cannabis users had significantly shorter hospital stays (8.02 days) and lower antipsychotic doses than the no-drug group (10.19 days).

The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI): a multicentre case-control study

Di Forti, Marta · 2019

This multicentre study across 11 sites in Europe and Brazil compared 901 people experiencing first-episode psychosis with 1,237 population controls.

Effects of cannabidiol (CBD) in neuropsychiatric disorders: A review of pre-clinical and clinical findings.

Elsaid, Sonja · 2019

CBD is safe, well-tolerated, and efficacious for several seizure disorders.

Synthetic cannabinoid use disorder: an update for general psychiatrists.

Grigg, Jasmin · 2019

Synthetic cannabinoid use is associated with more rapid development of dependence than cannabis, increased psychiatric risks, complex withdrawal syndromes, and serious physical adverse effects including seizures, cardiotoxicity, and death, suggesting a need for more intensive clinical management..

Cannabis and Psychosis: Are We any Closer to Understanding the Relationship?

Hamilton, Ian · 2019

The evidence for cannabis as a direct cause of schizophrenia has not been established.

How effective and safe is medical cannabis as a treatment of mental disorders? A systematic review.

Hoch, Eva · 2019

Across 14 RCTs (1,629 participants) covering dementia, cannabis/opioid dependence, psychosis, social anxiety, PTSD, anorexia nervosa, ADHD, and Tourette's disorder, cannabis-based medicines as adjuncts were associated with symptom improvements but not remission.

A systematic review of phytocannabinoid exposure on the endocannabinoid system: Implications for psychosis.

Jacobson, Maya R · 2019

The most established finding is CB1 receptor downregulation after chronic and recent cannabis exposure.

Is there a role for cannabidiol in psychiatry?

Khoury, Julia Machado · 2019

Evidence levels varied: B-level for cannabis withdrawal, C2 for cannabis addiction, C1 for positive symptoms in schizophrenia and anxiety in social anxiety disorder.

Cannabis and mental illness: a review.

Lowe, Darby J E · 2019

The review found increasing documentation of potential harms from cannabis use in patients with psychotic and mood disorders, while data supporting beneficial effects in psychiatric populations remains limited.

Demographic and clinical profiles of admitted psychiatric patients of the East London Mental Health Unit in the Eastern Cape, South Africa.

Madala-Witbooi, Nombulelo J · 2019

Schizophrenia (31.6%) and cannabis-related psychiatric disorders (31.6%) were tied as the most common reasons for psychiatric hospitalization, followed by bipolar type-1 disorder (21.9%) and alcohol-related disorders (15.5%).

Adolescent exposure to Δ9-tetrahydrocannabinol alters the transcriptional trajectory and dendritic architecture of prefrontal pyramidal neurons.

Miller, Michael L · 2019

THC exposure disrupted normal PFC development by inducing premature spine pruning and dendritic atrophy.

Impact of tobacco, alcohol and cannabis use on treatment outcomes among patients experiencing first episode psychosis: Data from the national RAISE-ETP study.

Oluwoye, Oladunni · 2019

At baseline, 50% of first-episode psychosis patients smoked tobacco, 28% used alcohol, and 24% used cannabis.

Cannabis use correlates with aggressive behavior and long-acting injectable antipsychotic treatment in Asian patients with schizophrenia.

Park, Seon-Cheol · 2019

After adjusting for multiple variables, lifetime cannabis use in Asian schizophrenia patients was independently associated with aggressive behavior (aOR 1.58, 95% CI 1.01-2.49) and with long-acting injectable antipsychotic treatment (aOR 1.80, 95% CI 1.44-2.82)..

Cannabis and Psychosis Through the Lens of DSM-5.

Pearson, Nathan T · 2019

Cannabis intoxication can produce transient psychotic symptoms.

Emergent Medical Illnesses Related to Cannabis Use.

Randall, Karen · 2019

Post-legalization ED presentations include cannabinoid hyperemesis, acute psychosis, cannabinoid catatonia syndrome, acute myo-pericarditis, pediatric ingestions, increases in fatal motor vehicle collisions, and hash-oil burn injuries.

Highs and lows of cannabinoid-dopamine interactions: effects of genetic variability and pharmacological modulation of catechol-O-methyl transferase on the acute response to delta-9-tetrahydrocannabinol in humans.

Ranganathan, Mohini · 2019

Val/Val individuals showed the greatest THC-induced working memory and attention deficits.

Antipsychotic treatment failure in patients with psychosis and co-morbid cannabis use: A systematic review.

Reid, Sam · 2019

Seven studies met inclusion criteria.

Legalized Cannabis in Colorado Emergency Departments: A Cautionary Review of Negative Health and Safety Effects.

Roberts, Brad A · 2019

The most concerning effects were psychosis, suicide, and other substance abuse.

Association of CNR1 genotypes with changes in neurocognitive performance after eighteen-month treatment in patients with first-episode psychosis.

Rojnic Kuzman, Martina · 2019

Carriers of the CNR1 rs7766029 CC genotype showed significantly greater improvement in verbal memory (Wechsler, Wechsler 30') and attention (Digit span F).

Endocannabinoid signaling in psychiatric disorders: a review of positron emission tomography studies.

Sloan, Matthew E · 2019

Cannabis users consistently had decreased CB1 receptor binding compared to controls, normalizing after short abstinence periods.

Psychotic patients who used cannabis frequently before illness onset have higher genetic predisposition to schizophrenia than those who did not.

Aas, M · 2018

Researchers assigned schizophrenia polygenic risk scores to 381 schizophrenia spectrum patients, 220 bipolar disorder spectrum patients, and 415 healthy controls.

Associations between adolescent cannabis use and brain structure in psychosis.

Abush, Hila · 2018

Researchers examined brain structure in 109 people with psychotic disorders, comparing those with and without a history of adolescent cannabis use.

Adolescent Synthetic Cannabinoid Exposure Produces Enduring Changes in Dopamine Neuron Activity in a Rodent Model of Schizophrenia Susceptibility.

Aguilar, David D · 2018

Researchers used a novel rodent model where about 40% of rats carry genetic susceptibility to a schizophrenia-like phenotype.

Differences in demographic and clinical characteristics between cannabis users and non-drug users: A retrospective study of patients at first hospitalization due to psychotic symptoms.

Balan Moshe, Livia · 2018

Researchers reviewed records of 318 patients at their first psychiatric hospitalization for psychotic symptoms, comparing 106 cannabis users (33%) to non-drug users.

Increased hippocampal engagement during learning as a marker of sensitivity to psychotomimetic effects of δ-9-THC.

Bhattacharyya, Sagnik · 2018

Researchers gave 36 healthy men either 10 mg oral THC or placebo in a randomized crossover design and measured both psychotic symptoms and brain activity during a verbal learning task using fMRI.

Maternal and paternal cannabis use during pregnancy and the risk of psychotic-like experiences in the offspring.

Bolhuis, Koen · 2018

Researchers followed 3,692 children from the Generation R birth cohort to examine whether parental cannabis use during pregnancy affected the risk of psychotic-like experiences at age 10.

Synthetic and Non-synthetic Cannabinoid Drugs and Their Adverse Effects-A Review From Public Health Prospective.

Cohen, Koby · 2018

Researchers reviewed the epidemiology and health effects of synthetic cannabinoids compared to natural cannabis from a public health perspective.

Longitudinal assessment of the effect of cannabis use on hospital readmission rates in early psychosis: A 6-year follow-up in an inpatient cohort.

Colizzi, Marco · 2018

Researchers followed 161 patients admitted to an early psychosis intervention unit for 6 years, tracking hospital readmissions and total time spent hospitalized.

Previous cannabis exposure modulates the acute effects of delta-9-tetrahydrocannabinol on attentional salience and fear processing.

Colizzi, Marco · 2018

Twenty-four healthy men participated in a double-blind THC challenge study, divided into 12 never-users (fewer than 5 lifetime joints) and 12 abstinent modest users (about 25 lifetime joints).

Modulation of acute effects of delta-9-tetrahydrocannabinol on psychotomimetic effects, cognition and brain function by previous cannabis exposure.

Colizzi, Marco · 2018

Using the same 24-participant THC challenge design, this companion study focused on cognitive processing and psychotomimetic effects.

The effect of interactions between genetics and cannabis use on neurocognition. A review.

Cosker, E · 2018

Researchers systematically reviewed 13 studies examining how genetic variations influence the cognitive effects of cannabis use.

Translational Investigation of the Therapeutic Potential of Cannabidiol (CBD): Toward a New Age.

Crippa, José A · 2018

Brazilian researchers who have been at the forefront of CBD research reviewed the translational evidence, from basic science to clinical application, for CBD across multiple neuropsychiatric conditions. The most established properties of CBD include anxiolytic (anxiety-reducing), antipsychotic, and neuroprotective effects.

The Psychiatric Consequences of Cannabinoids.

De Aquino, Joao P · 2018

This overview examined the psychiatric effects of both plant-based and synthetic cannabinoids across different timeframes. Acutely, cannabinoids produce multiphasic, dose-dependent effects on anxiety, mood, and perception while impairing cognition and psychomotor function.

Psychosis and synthetic cannabinoids.

Deng, Huiqiong · 2018

Researchers reviewed the clinical literature on psychotic symptoms following synthetic cannabinoid (SC) use. Multiple clinical reports documented induction of psychotic symptoms after consuming SC products, including both new-onset psychosis in people with no psychiatric history and psychotic relapses in those with prior episodes. The review found that the relationship between SCs and psychosis is more complex than any single chemical component can explain.

The Potential of Cannabidiol Treatment for Cannabis Users With Recent-Onset Psychosis.

Hahn, Britta · 2018

This review examined the potential of CBD as a treatment specifically for cannabis users with recent-onset psychosis, a population with currently poor outcomes and no specialized effective intervention. Cannabis misuse is a major factor associated with poor outcomes after a first psychotic break and is especially common in individuals with recent-onset psychosis.

Cortical thickness, cortical surface area and subcortical volumes in schizophrenia and bipolar disorder patients with cannabis use.

Hartberg, Cecilie Bhandari · 2018

Researchers compared brain scans of patients with schizophrenia or bipolar disorder who had used cannabis (132 patients) against those who had not (182 patients) and 277 healthy controls. After controlling for confounders including tobacco and alcohol use, cannabis-using patients showed reduced cortical thickness in the caudal middle frontal gyrus compared to non-user patients and healthy controls. However, when patients with co-occurring alcohol and other illicit drug use were excluded, these findings were no longer significant.

Genetic vulnerability to schizophrenia is associated with cannabis use patterns during adolescence.

Hiemstra, Marieke · 2018

Researchers followed 372 adolescents from the RADAR-Y study, tracking substance use from ages 13-20 while measuring each participant's genetic vulnerability to schizophrenia using polygenic risk scores. High schizophrenia genetic vulnerability was specifically associated with a stronger increase in cannabis use during ages 16-20.

Spicing it up - synthetic cannabinoid receptor agonists and psychosis - a systematic review.

Hobbs, Melissa · 2018

Researchers synthesized evidence from 2 toxicology reports, 4 case-control studies, 3 cross-sectional studies, and 15 case reports on synthetic cannabinoid receptor agonists (SCRAs) and psychosis. The toxicology reports identified toxic psychosis and delirium (40%), agitation (10%), and hallucinations (4-7%) as main presenting features.

Comparing the effect of clozapine and risperidone on cue reactivity in male patients with schizophrenia and a cannabis use disorder: A randomized fMRI study.

Machielsen, Marise W J · 2018

Thirty-eight patients with schizophrenia (30 with cannabis use disorder, 8 without) and 20 healthy controls were included.

Pharmacological properties of cannabidiol in the treatment of psychiatric disorders: a critical overview.

Mandolini, G M · 2018

Researchers reviewed all clinical studies investigating CBD as treatment for psychiatric symptoms and linked findings to pharmacological mechanisms. For schizophrenia: CBD may exert antipsychotic effects primarily through facilitation of endocannabinoid signaling and CB1 receptor antagonism.

Subcortical Local Functional Hyperconnectivity in Cannabis Dependence.

Manza, Peter · 2018

Researchers examined resting-state brain connectivity in subcortical regions using data from 441 young adults in the Human Connectome Project. Thirty cannabis-dependent subjects were compared to 30 controls matched on age, sex, education, BMI, anxiety, depression, and alcohol/tobacco use. Cannabis-dependent individuals showed markedly increased local functional connectivity in several subcortical regions: ventral striatum (where the nucleus accumbens is located), midbrain (where dopamine-producing neurons reside), brainstem, and lateral thalamus. These hyperconnectivity effects occurred without significant differences in subcortical brain volumes. The effects were most pronounced in individuals who began cannabis use earliest in life and who reported high levels of negative emotionality. The researchers interpreted these findings as reflecting changes in dopaminergic circuits implicated in both psychosis and habit formation/reward processing..

Cannabis, a Significant Risk Factor for Violent Behavior in the Early Phase Psychosis. Two Patterns of Interaction of Factors Increase the Risk of Violent Behavior: Cannabis Use Disorder and Impulsivity; Cannabis Use Disorder, Lack of Insight and Treatment Adherence.

Moulin, Valerie · 2018

Researchers studied 265 early psychosis patients to understand how cannabis use disorder interacts with other risk factors for violent behavior. Cannabis use disorder was independently associated with violent behavior during treatment. Classification and Regression Tree (CART) analysis revealed two distinct patient profiles with elevated violence rates: 1.

Demographic and socioenvironmental predictors of premorbid marijuana use among patients with first-episode psychosis.

Pauselli, Luca · 2018

Researchers examined what predicted premorbid marijuana use patterns in 247 patients with first-episode psychosis. Three marijuana use variables were studied: age at initiation, escalation trajectory in the five years before psychosis onset, and cumulative dose. Age at initiation of cigarette smoking was the strongest predictor, linked to all three marijuana variables: earlier marijuana initiation, faster escalation to daily use, and higher cumulative dose. During childhood, poorer academic performance predicted earlier marijuana initiation, while poorer sociability was related to faster escalation and higher cumulative dose. Experiencing euphoric effects from marijuana was positively correlated with escalation and cumulative dose, but having negative experiences was unrelated. Traumatic childhood/adolescent experiences correlated with rapid escalation and amount used, but not with age of initiation..

Impact of substance use disorder on gray matter volume in schizophrenia.

Quinn, Margaret · 2018

Using voxel-based morphometry, researchers found that schizophrenia patients had reduced gray matter in several brain regions regardless of substance use history.

Comorbid Cannabis and Tobacco Use Disorders in Hospitalized Patients with Psychotic-Spectrum Disorders.

Reeves, Lauren E · 2018

Patients with both cannabis and tobacco use disorders (CUD + TUD) had significantly higher odds of also having alcohol and stimulant use disorders compared to patients with neither.

Effects of Adolescent THC Exposure on the Prefrontal GABAergic System: Implications for Schizophrenia-Related Psychopathology.

Renard, Justine · 2018

The review synthesizes evidence that adolescent THC exposure targets schizophrenia-related molecular pathways in the prefrontal cortex and mesolimbic dopamine system.

Effects of cannabis use on body mass, fasting glucose and lipids during the first 12 months of treatment in schizophrenia spectrum disorders.

Scheffler, F · 2018

There was a significant group-by-time interaction (p=0.002): cannabis-negative patients showed greater BMI increases over 12 months than cannabis-positive patients.

Patterns in adolescent cannabis use predict the onset and symptom structure of schizophrenia-spectrum disorder.

Shahzade, C · 2018

Factor analysis of cannabis use motives produced four groups (sedation, stimulation, social pressure, recreation).

Cannabinoid-glutamate interactions and neural oscillations: implications for psychosis.

Sherif, Mohamed A · 2018

CB1Rs and NMDARs have direct and indirect interactions in brain regions implicated in schizophrenia (hippocampus, frontal cortex, cerebellum).

Cannabinoid receptor-mediated disruption of sensory gating and neural oscillations: A translational study in rats and humans.

Skosnik, Patrick D · 2018

Both THC and THC+CBD disrupted P50 sensory gating in humans and reduced evoked theta and gamma oscillations.

Is cannabis a risk factor for suicide attempts in men and women with psychotic illness?

Waterreus, A · 2018

In unadjusted analyses, daily cannabis users of both sexes had significantly increased odds of suicide attempts.

Cannabis; Epidemiological, Neurobiological and Psychopathological Issues: An Update.

De Luca, Maria Antonietta · 2017

The review synthesized evidence across three domains.

Cannabis and Canada's children and youth.

Grant, Christina N · 2017

Cannabis is the most common illicit drug used by Canadian teenagers.

Smoking status and its relationship to demographic and clinical characteristics in first episode psychosis.

Grossman, Michael · 2017

In 140 patients entering specialized first-episode psychosis treatment, 53% smoked cigarettes: 47 were light/moderate smokers (1-19/day) and 27 were heavy smokers (20+/day).

Cannabis and development of dual diagnoses: A literature review.

Hanna, Rebecca C · 2017

This narrative review examined the relationship between cannabis use and psychiatric disorders across multiple categories.

Heavy cannabis use prior psychosis in schizophrenia: clinical, cognitive and neurological evidences for a new endophenotype?

Mallet, Jasmina · 2017

This study compared 34 schizophrenia patients who reported heavy cannabis use before their first psychotic episode with 27 patients who did not. The results were counterintuitive: heavy pre-psychosis cannabis users showed significantly fewer neurological soft signs (subtle neurological abnormalities considered markers of early neurodevelopmental impairment) and better cognitive functioning across multiple domains including reaction time, episodic memory, and visuoconstructive abilities. These findings held after controlling for alcohol and tobacco use.

Adverse Structural and Functional Effects of Marijuana on the Brain: Evidence Reviewed.

Mandelbaum, David E · 2017

This critical review focused specifically on evidence for structural and functional brain damage from cannabis, combined with neuropathological findings from a fatal case of cannabis-induced psychosis. The literature review found strong evidence that chronic cannabis abuse causes cognitive impairment and brain damage, particularly to white matter (the brain's communication cables), where CB1 cannabinoid receptors are abundant. The fatal case provided direct neuropathological evidence of white matter damage in a person who died from cannabis-induced psychosis, complementing the imaging-based evidence from living subjects. Regarding therapeutic claims, the review concluded that contrary to popular perception, there are few objective data supporting preferential use of cannabis over conventional therapy for neurological conditions such as multiple sclerosis, epilepsy, or schizophrenia.

Cannabis use, COMT, BDNF and age at first-episode psychosis.

Mané, Anna · 2017

This study investigated whether cannabis use and two genes (COMT Val158Met and BDNF Val66Met) interact to influence when psychosis first appears. Among 260 Caucasian first-episode psychosis patients, two factors independently predicted younger age at psychosis onset: early cannabis use and carrying the met-allele of the BDNF Val66Met polymorphism. The BDNF finding is significant because BDNF (brain-derived neurotrophic factor) is critical for brain development and neural plasticity.

Opposing Effects of Cannabis Use on Late Auditory Repetition Suppression in Schizophrenia Patients and Healthy Control Subjects.

Rentzsch, Johannes · 2017

Researchers measured how the brain filters repeated auditory signals in four groups: schizophrenia patients with and without cannabis use, and healthy controls with and without cannabis use.

A review of Indian research on co-occurring cannabis use disorders& psychiatric disorders.

Singh, Shalini · 2017

The review identified 52 published Indian studies on co-occurring cannabis use disorders and psychiatric conditions.

Pros and Cons of Medical Cannabis use by People with Chronic Brain Disorders.

Suryadevara, Uma · 2017

The review examined evidence on cannabis use across six brain disorders, finding a mixed picture that varied dramatically by condition. Neurological disorders with some benefit: Cannabis reduced pain and spasticity in multiple sclerosis, decreased tremor, rigidity, and pain in Parkinson's disease, and improved quality of life in ALS by helping appetite, pain, and spasticity.

Synthetic Cathinone and Cannabinoid Designer Drugs Pose a Major Risk for Public Health.

Weinstein, Aviv M · 2017

The review compared synthetic cannabinoids to natural cannabis across several dimensions.

The Changing Drug Culture: Emerging Drugs of Abuse and Legal Highs.

Albertson, Timothy E · 2016

This review for family practitioners cataloged the expanding landscape of synthetic recreational drugs.

Marijuana use in the immediate 5-year premorbid period is associated with increased risk of onset of schizophrenia and related psychotic disorders.

Kelley, Mary E · 2016

This study examined 247 people experiencing their first episode of psychosis to determine whether marijuana use in the preceding years was temporally linked to psychosis onset. Escalation of marijuana use in the 5 years before psychosis onset was highly predictive.

Attentional dysfunction in abstinent long-term cannabis users with and without schizophrenia.

Rentzsch, Johannes · 2016

Researchers measured attention-related brainwave responses (P300) in four groups: schizophrenia patients with and without chronic cannabis use, and healthy controls with and without chronic cannabis use.

Cannabidiol as a Potential New Type of an Antipsychotic. A Critical Review of the Evidence.

Rohleder, Cathrin · 2016

This review examined the evidence for cannabidiol (CBD) as a potential antipsychotic medication.

The impact of cannabis use on clinical outcomes in recent onset psychosis.

Barrowclough, Christine · 2015

This study followed 110 people with early psychosis who also had cannabis abuse or dependence, measuring their substance use and symptoms at four time points over 18 months.

Impairment of inhibitory control processing related to acute psychotomimetic effects of cannabis.

Bhattacharyya, Sagnik · 2015

Researchers gave 36 healthy men with minimal cannabis exposure either 10mg of oral THC or placebo in a double-blind crossover design, then scanned their brains during a task requiring them to withhold automatic responses (Go/No-Go task). THC increased inhibition errors and reduced inhibition efficiency compared to placebo.

Cannabinoid modulation of functional connectivity within regions processing attentional salience.

Bhattacharyya, Sagnik · 2015

Researchers administered THC, CBD, or placebo to healthy occasional cannabis users and scanned their brains during a task involving processing novel and salient stimuli.

Cannabis use and mania symptoms: a systematic review and meta-analysis.

Gibbs, Melanie · 2015

Researchers conducted a systematic review following PRISMA guidelines, searching five databases for prospective studies on cannabis use and mania.

Acute effects of delta-9-tetrahydrocannabinol, cannabidiol and their combination on facial emotion recognition: a randomised, double-blind, placebo-controlled study in cannabis users.

Hindocha, Chandni · 2015

Forty-eight cannabis users received THC (8mg), CBD (16mg), THC+CBD (8mg+16mg), and placebo by inhalation in a four-way crossover design.

The complex etiology of schizophrenia - general state of the art.

Hosák, Ladislav · 2015

This review synthesized the complex, multi-factorial etiology of schizophrenia.

Psychotic experiences are linked to cannabis use in adolescents in the community because of common underlying environmental risk factors.

Shakoor, Sania · 2015

Researchers used data from 4,830 twin pairs (aged 16) to determine whether the cannabis-psychosis association is driven by genetics, shared environment, or unique environment. Cannabis use was modestly heritable (37%) with strong shared environmental influence (55%).

Cannabis use and first manic episode.

Bally, Nathalie · 2014

This review examined the relationship between cannabis use and the onset of mania in bipolar disorder.

Cannabidiol: pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders.

Devinsky, Orrin · 2014

This landmark review by leading researchers summarized the evidence for CBD across multiple neuropsychiatric conditions.

Executive attention impairment in adolescents with schizophrenia who have used cannabis.

Epstein, Katherine A · 2014

Researchers compared attention performance across four groups of adolescents: early-onset schizophrenia with cannabis use disorder (EOS+CUD, n=18), schizophrenia only (EOS, n=34), cannabis use disorder only (CUD, n=29), and healthy controls (n=53).

The effect of clozapine and risperidone on attentional bias in patients with schizophrenia and a cannabis use disorder: An fMRI study.

Machielsen, Marise Wj · 2014

In a randomized trial of 36 patients with schizophrenia and cannabis use disorder, those treated with clozapine showed larger reductions in subjective craving and decreased activation of the insula during a cannabis-word Stroop task compared to those on risperidone.

Cannabinoids and schizophrenia: therapeutic prospects.

Robson, P J · 2014

Standard antipsychotic drugs fail to adequately control symptoms in approximately one-third of schizophrenia patients.

Cannabis use and first-episode psychosis: relationship with manic and psychotic symptoms, and with age at presentation.

Stone, J M · 2014

In 502 patients with first-episode psychosis tracked across London-based Early Intervention teams, cannabis use level was associated with younger age at presentation to services and with manic symptoms and conceptual disorganization, but not with delusions, hallucinations, negative symptoms, or daily functioning. The most striking finding was in the longitudinal data: cannabis users who reduced or stopped their use following initial contact with psychiatric services showed the greatest improvement in symptoms at one year, compared to both continued users and non-users.

Immune system: a possible nexus between cannabinoids and psychosis.

Suárez-Pinilla, Paula · 2014

The review identified a clear dichotomy: endocannabinoids (produced naturally in the body) generally enhanced immune responses, while exogenous cannabinoids (from cannabis) had immunosuppressant effects.

Cannabis affects people differently: inter-subject variation in the psychotogenic effects of Δ9-tetrahydrocannabinol: a functional magnetic resonance imaging study with healthy volunteers.

Atakan, Z · 2013

In a double-blind, placebo-controlled study, 21 healthy men with minimal cannabis experience received 10 mg oral THC or placebo.

The pharmacologic and clinical effects of medical cannabis.

Borgelt, Laura M · 2013

The review covered three types of cannabinoid medicines available in North America: dronabinol (Schedule III), nabilone (Schedule II), and medical cannabis (Schedule I).

Changes in cannabis use among young people: impact on mental health.

Copeland, Jan · 2013

The review examined current trends in youth cannabis use and their mental health implications.

Cannabis abuse and brain morphology in schizophrenia: a review of the available evidence.

Malchow, Berend · 2013

The review examined MRI studies comparing schizophrenia patients with and without cannabis abuse, as well as high-risk individuals.

Effects of cannabis use on event related potentials in subjects at ultra high risk for psychosis and healthy controls.

van Tricht, Mirjam J · 2013

Researchers measured brain wave responses (event-related potentials, or ERPs) in 48 ultra-high-risk (UHR) subjects and 50 healthy controls, split into cannabis users and non-users within each group.

Blurred boundaries: the therapeutics and politics of medical marijuana.

Bostwick, J Michael · 2012

This extensive review covered the full landscape of cannabis issues circa 2012.

Resting state abnormalities in psychosis compared to acute cannabinoids and opioids challenges: a systematic review of functional imaging studies.

Denier, Niklaus · 2012

This systematic review compared resting-state brain activity in three conditions: first-episode psychosis (FEP), acute cannabinoid effects, and acute opioid effects, using data from 22 neuroimaging studies. Results within each condition group were highly conflicting, with different studies showing different patterns.

The effect of cannabis use and cognitive reserve on age at onset and psychosis outcomes in first-episode schizophrenia.

Leeson, Verity C · 2012

Ninety-nine first-episode schizophrenia patients were divided into lifetime cannabis users and never-users.

Acute effects of a single, oral dose of d9-tetrahydrocannabinol (THC) and cannabidiol (CBD) administration in healthy volunteers.

Martin-Santos, R · 2012

Sixteen healthy male volunteers received oral THC (10 mg), CBD (600 mg), or placebo in a double-blind crossover design with one-month intervals between sessions.

Psychopathologic differences between cannabis-induced psychoses and recent-onset primary psychoses with abuse of cannabis.

Rubio, Gabriel · 2012

Among 181 patients with psychotic symptoms and cannabis use, 50 were diagnosed with cannabis-induced psychotic disorder (CIPD) and 104 with primary psychotic disorders.

Cannabidiol in humans-the quest for therapeutic targets.

Zhornitsky, Simon · 2012

The review identified 34 studies: 16 in healthy subjects and 18 in clinical populations covering MS, schizophrenia, bipolar mania, social anxiety, pain, cancer, Huntington's disease, insomnia, and epilepsy. Key findings included: high inhaled/IV doses of CBD were needed to block THC effects.

Adverse effects of cannabis.

· 2011

This comprehensive review examined multiple categories of cannabis adverse effects using systematic methodology. Acute effects included mental slowness, impaired reaction times, and occasionally heightened anxiety.

Early intervention for psychosis.

Marshall, Max · 2011

This Cochrane systematic review examined whether early intervention could improve outcomes in psychosis across 18 RCTs with 1,808 participants. For psychosis prevention in prodromal patients: olanzapine showed little benefit, CBT was similarly inconclusive, risperidone plus CBT showed short-term benefit at 6 months but not 12 months, and omega-3 fatty acids showed a promising but unreplicated result. For first-episode psychosis treatment: specialized early intervention teams showed some benefit for treatment retention and independent living at 5 years.

Modulation of auditory and visual processing by delta-9-tetrahydrocannabinol and cannabidiol: an FMRI study.

Winton-Brown, Toby T · 2011

Fourteen healthy volunteers were scanned with fMRI on three occasions after receiving THC (10 mg), CBD (600 mg), or placebo.

Treatment of cannabis use among people with psychotic or depressive disorders: a systematic review.

Baker, Amanda L · 2010

From 1,713 initial articles, only 7 randomized controlled trials reported cannabis use outcomes from pharmacological or psychological interventions in mental health patients. The limited evidence suggested two key findings: 1.

Opposite effects of delta-9-tetrahydrocannabinol and cannabidiol on human brain function and psychopathology.

Bhattacharyya, Sagnik · 2010

In a two-part study, 15 healthy men completed four tasks during fMRI after receiving THC (10 mg), CBD (600 mg), or placebo. THC and CBD had opposite effects on brain activation across all four tasks: - In the striatum during verbal recall - In the hippocampus during response inhibition - In the amygdala while viewing fearful faces - In the superior temporal cortex during speech processing - In the occipital cortex during visual processing In a second experiment with 6 volunteers, CBD pretreatment prevented the acute psychotic symptoms normally induced by intravenous THC. This demonstrated that the two main cannabis compounds have fundamentally opposing brain effects, and that CBD can actively block THC-induced psychosis..

Enhancement drugs: are there limits to what we should enhance and why?

Hesse, Morten · 2010

This commentary made two specific harm-reduction proposals: For alcohol: adding dissolved oxygen could reduce accident risk and liver damage. For cannabis: strong evidence indicated that reducing THC content and increasing CBD content could reduce the risk of psychosis and addiction associated with cannabis use. The author argued that public health interventions should focus on reducing concrete harms rather than making moral judgments about which human experiences should or should not be enhanced through substance use. The central proposition was that responsible regulation should not be limited to preventing or reducing use, but should include strategies to reduce the burden of illness associated with substance use..

Diffusion tensor imaging in the early phase of schizophrenia: what have we learned?

Peters, Bart D · 2010

The review examined diffusion tensor imaging (DTI) studies in first-episode schizophrenia patients and people at high risk for psychosis.

Cannabis use and cognitive functioning in first-episode schizophrenia patients.

Rodríguez-Sánchez, José Manuel · 2010

Researchers compared cognitive functioning between cannabis-using and non-using patients with first-episode schizophrenia.

Psychopathological and cognitive effects of therapeutic cannabinoids in multiple sclerosis: a double-blind, placebo controlled, crossover study.

Aragona, Massimiliano · 2009

Seventeen cannabis-naive MS patients were randomized in a double-blind crossover trial to receive Sativex or placebo for 3-week periods, with comprehensive psychological and cognitive assessments. No significant differences were found between the Sativex and placebo phases on any measured psychological or cognitive variable.

Does cannabis use affect treatment outcome in bipolar disorder? A longitudinal analysis.

van Rossum, Inge · 2009

In an observational study of 3,459 bipolar disorder patients (both inpatient and outpatient), researchers tracked the influence of cannabis use on treatment outcomes over one year. Cannabis users exhibited less medication compliance and higher levels of overall illness severity, mania, and psychosis compared to non-users throughout the 12-month treatment period. Cannabis users also experienced less life satisfaction and had a lower probability of being in a relationship. There was little evidence that these associations were explained by third variables (mediators), suggesting an independent impact of cannabis on clinical outcomes in bipolar disorder. The impact on psychopathological outcomes was pronounced, while the impact on social outcomes was more modest..

Effects of acute oral Delta9-tetrahydrocannabinol and standardized cannabis extract on the auditory P300 event-related potential in healthy volunteers.

Roser, Patrik · 2008

In a double-blind crossover study, 20 healthy volunteers received pure THC, a standardized cannabis extract containing THC and CBD, or placebo on separate occasions. As expected, pure THC significantly reduced P300 amplitude at frontal, central, and parietal electrodes.

A comparison of symptoms and family history in schizophrenia with and without prior cannabis use: implications for the concept of cannabis psychosis.

Boydell, J · 2007

The study examined 757 people experiencing their first episode of schizophrenia, of whom 182 (24%) had used cannabis in the year before their first presentation. After controlling for age, sex, and ethnicity, researchers found no statistically significant differences in any measured symptom between cannabis users and non-users.

Acute effects of Delta9-tetrahydrocannabinol and standardized cannabis extract on the auditory evoked mismatch negativity.

Juckel, Georg · 2007

In a double-blind, placebo-controlled crossover study, 22 healthy volunteers received either pure THC, a standardized cannabis extract containing both THC and CBD, or placebo on separate occasions. The cannabis extract (THC + CBD) produced significantly greater mismatch negativity (MMN) amplitudes at central brain electrodes compared to both placebo and pure THC.

Comorbid substance use and age at onset of schizophrenia.

Barnes, Thomas R E · 2006

Researchers studied 152 people recruited to the West London First-Episode Schizophrenia Study.

Changes in cannabis use and its consequences over 3 years in a remote indigenous population in northern Australia.

Clough, Alan R · 2006

Researchers conducted a 3-year follow-up in remote Aboriginal communities in Arnhem Land, Northern Territory, Australia.

Comorbidity: cannabis and complexity.

Raphael, Beverley · 2005

This review covered multiple dimensions of cannabis health effects and comorbidity.

The safety of cannabinoids for the treatment of multiple sclerosis.

Smith, Paul F · 2005

This review assessed the safety profile of cannabis-based medicinal extracts (CBMEs) for MS treatment.

Cannabis use and age at onset of schizophrenia.

Veen, Natalie D · 2004

Researchers conducted a population-based, first-contact incidence study in The Hague, Netherlands, examining 133 schizophrenia patients.

Precipitation and determination of the onset and course of schizophrenia by substance abuse--a retrospective and prospective study of 232 population-based first illness episodes.

Bühler, Babette · 2002

People experiencing their first episode of schizophrenia were twice as likely as controls to have a lifetime history of substance abuse (alcohol abuse: 23.7% vs 12.3%; drug abuse: 14.2% vs 7.0%).

Cannabis, vulnerability, and the onset of schizophrenia: an epidemiological perspective.

Hambrecht, M · 2000

From a German population of 1.5 million, researchers identified 232 first-episode schizophrenia patients and carefully mapped the timeline of cannabis abuse relative to the onset of psychotic symptoms. Thirteen percent had a history of cannabis abuse, double the rate in matched controls.

The Paradoxical Effect of Cannabis Use on Cognition in Chronic Psychotic Disorders.

Gorea, Fiorela · 2026

In 105 psychiatric inpatients with psychotic disorders, cannabis users had higher MoCA (Montreal Cognitive Assessment, a brief test of thinking skills) scores than non-users.

Identifying established human placental markers of schizophrenia in rodents after gestational ∆9-tetrahydrocannabinol exposure†.

Kocsis, Andrea M · 2026

This study tested whether prenatal THC exposure in rats would alter the same placental genes that human genomic studies have linked to schizophrenia risk.

Psychotic Risk Associated With Cannabinoid Use: A Case Report of Ekbom-Like Delusional Infestation.

Pao Trigo, Miguel · 2026

A man with decades of daily cannabis use presented with persistent pruritus, tactile hallucinations, and a fixed belief that parasites infested his skin.

Kynurenine amplifies tetrahydrocannabinol-induced sensorimotor impairment and classic "tetrad" effects in mice.

Bilel, Sabrine · 2025

Mice given kynurenine before THC showed significantly worse sensorimotor responses, greater motor impairment, and deeper hypothermia compared to THC alone.

A pilot randomized controlled trial of a digital cannabis harm reduction intervention for young adults with first-episode psychosis who use cannabis.

Coronado-Montoya, Stephanie · 2025

Trial retention was 82.2% and CHAMPS completion rate was 58.8%, meeting pre-specified thresholds for feasibility and acceptability.

Prenatal Delta-9-Tetrahydrocannabinol Exposure Induces Transcriptional Alterations in Dopaminergic System with Associated Electrophysiological Dysregulation in the Prefrontal Cortex of Adolescent Rats.

Di Bartolomeo, Martina · 2025

Prenatal cannabis exposure increased mRNA levels of dopamine D1 and D2 receptors in the prefrontal cortex, with a particularly strong effect on D2 in males.

Cannabidiol attenuates behavioral and electrophysiological changes in the MAM model of schizophrenia in male and female rats.

Fabris, Débora · 2025

Both male and female MAM rats showed increased VTA dopamine neuron population activity, which was reversed by CBD (60 mg/kg) in both sexes.

Parent Perspectives on Youth Cannabis Use and Mental Health: Impacts, Challenges, and Recommendations.

Gerhardt, T Freeman · 2025

Parents reported four themes: cannabis use worsened or triggered mental health crises; it created emotional and financial burdens on families; healthcare providers often minimized cannabis risks during treatment; and parents called for better public health warnings and regulatory oversight..

A Qualitative Study of Cannabis Use and Family Dynamics Among Youth in Early Psychosis Programs.

Ghelani, Amar · 2025

Participants described five themes: parental disapproval driven by psychosis concerns, intra-family cannabis consumption, family influence on use patterns, changing parental attitudes over time, and increased closeness with family members who also use cannabis..

Cannabis involvement and mass shooting events in the United States from 1900 to 2019.

Girgis, R R · 2025

Among mass shooters, cannabis involvement (use, possession, or distribution) was significantly higher from 1996 onward compared to before (11.2% vs 4.9%, p=0.002).

Endocannabinoid system alterations in schizophrenia: association with cannabis use and antipsychotic medication.

Haddad, Natalia Mansur · 2025

In a study of 93 individuals (29 treatment-resistant schizophrenia on clozapine, 31 on other antipsychotics, 33 controls), those reporting lifetime cannabis use had significantly lower plasma 2-AG levels (p=0.011), and this remained the only significant factor in models controlling for confounders.

Adolescents and cannabis in the 21st century: Current Problems in Pediatric and Adolescent Health Care.

Itriyeva, Khalida · 2025

This comprehensive review covers three decades of adolescent cannabis trends in the United States, and the picture it paints is more complicated than either "legalization is harmless" or "legalization is catastrophic" narratives suggest. Teenage use rates have remained remarkably stable despite legalization.

Qualitative interviews with young adults at risk for psychosis and who use Cannabis: Informing the development of a mobile intervention.

Merrill, Jennifer E · 2025

Five key barriers to reducing cannabis emerged: using cannabis to cope, social influences, dependence symptoms, easy access, and ambivalence about change.

Exploring the impact of drug decriminalization and legalization policies on mental health outcomes: A scoping review.

Mohebbian, Mana · 2025

As drug policies liberalize worldwide, a central concern is whether this will worsen mental health outcomes.

A Hidden Mark of a Troubled Past: Neuroimaging and Transcriptomic Analyses Reveal Interactive Effects of Maternal Immune Activation and Adolescent THC Exposure Suggestive of Increased Neuropsychiatric Risk.

Moreno-Fernández, Mario · 2025

While adolescent THC did not trigger visible behavioral disruptions, PET brain scans revealed alterations dependent on the combination of prenatal immune activation and THC.

Prophylactic efficacy of cannabidiol and sodium nitroprusside in a ketamine-model of schizophrenia: sex-dependent effects on positive-like and cognitive impairments.

Prado, Daniel B A · 2025

Rats pretreated with CBD and sodium nitroprusside (SNP) during brain development (postnatal days 12-32) and later challenged with ketamine showed sex-dependent responses.

Evaluating Delta-8-THC-Induced Psychosis: A Systematic Review.

Ralston, Megan Jayne · 2025

From 201 studies screened, 12 met criteria and 6 case reports involving 9 patients were reviewed.

Altered network function in hippocampus after sub-chronic activation of Cannabis receptors in peri-adolescence.

Rehn, Johanna · 2025

This is the preprint (bioRxiv) version of the study published as RTHC-00197.

Cannabidiol reverses microglia activation and deficits of parvalbumin interneurons and their perineuronal nets in a MK-801-induced mouse model of schizophrenia.

Rodrigues da Silva, Naielly · 2025

Chronic MK-801 treatment (an NMDA receptor blocker) caused memory deficits and reduced gamma brain wave power in mice.

Genetic Insights into Cannabis-induced Psychosis: Role of CNR1 Gene Mutation (rs1049353) and Implications- A Cross-sectional Study.

Sahoo, Sujata · 2025

Not everyone who uses cannabis develops psychosis, and not everyone with schizophrenia has used cannabis.

Cannabis-Induced Catatonia Complicated by Rhabdomyolysis, Acute Kidney Injury, and Sympathetic Overactivity: A Case Report.

Saira, Sidharth · 2025

This case report describes a severe psychiatric emergency triggered by cannabis in a vulnerable individual.

Pain Is Not a Predictor of Cannabis Use in People With Psychotic Disorders.

Smid, Mirjam H · 2025

Pain and interference from pain were not significant predictors of cannabis use (yes/no) or amount of cannabis use in people with psychotic disorders.

Partial Dopamine D2/3 Agonists and Dual Disorders: A Retrospective-Cohort Study in a Real-World Clinical Setting on Patients with Schizophrenia Spectrum Disorders and Cannabis Use Disorder.

Trovini, Giada · 2025

Partial D2/D3 agonists (aripiprazole, brexpiprazole, cariprazine) have unique pharmacology: they activate dopamine receptors enough to prevent withdrawal/craving but not enough to worsen psychosis.

Development of a motivational enhancement therapy cannabis-reduction intervention for young adults experiencing psychosis: A feasibility pilot study.

Walker, Denise D · 2025

The Cannabis Check-Up for Psychosis (CCU-P) — a two-session motivational enhancement therapy intervention — demonstrated 92% completion rate (11 of 12 completed both sessions), high satisfaction ratings, and all participants said they would recommend it to others in Coordinated Specialty Care..

Unraveling Cannabidiol's Dual Modulatory Role in Schizophrenia: Network Pharmacology and In Vivo Validation of Neuroinflammatory and Behavioral Modulation.

Wei, Ying · 2025

RTHC-00193 reviewed clinical evidence that CBD may have therapeutic potential for schizophrenia.

Serum brain-derived neurotrophic factor level and its relation with cannabis use disorder and schizophrenia: A cross-sectional exploratory study in patients at a tertiary care hospital.

George, Aishwariya Brigit · 2024

BDNF levels differed significantly across four groups of 20 subjects each.

Epigenetic effects of cannabis: A systematic scoping review of behavioral and emotional symptoms associated with cannabis use and exocannabinoid exposure.

Machado, Ana Sofia · 2024

Across 37 included studies, cannabis exposure was most consistently associated with global hypomethylation and changes at specific genes related to dopamine signaling (DRD2, COMT), cellular function (AKT1, STAT3), and neural development (NCAM1, DLGAP2).

Lack of interactions between prenatal immune activation and Δ9-tetrahydrocannabinol exposure during adolescence in behaviours relevant to symptom dimensions of schizophrenia in rats.

Moreno-Fernández, Mario · 2024

MIA impaired working memory and sensorimotor gating but surprisingly increased sociability.

Recurrent cannabis-induced catatonia: a case report and comprehensive systematic literature review.

Moshfeghinia, Reza · 2024

A 23-year-old male developed mutism, social isolation, and fixed gaze after cannabis use.

Substance use and lifestyle risk factors for somatic disorders among psychiatric patients in Greenland.

Nielsen, Ida Margrethe · 2024

In 104 patients with psychotic disorders in Nuuk, 68% had harmful cannabis use, 80%+ were daily smokers, 50%+ had dyslipidemia, 25%+ obese, 18% hypertension, 6% diabetes..

Role of cyclin-dependent kinase 5 in psychosis and the modulatory effects of cannabinoids.

Barrera-Conde, Marta · 2023

First-episode psychosis patients with prior cannabis use (FEP/c) had lower CDK5 and higher PSD95 levels compared to those without cannabis use (FEP/nc), and showed fewer social functioning deficits.

Cognitive dysfunction and impaired neuroplasticity following repeated exposure to the synthetic cannabinoid JWH-018 in male mice.

Bilel, Sabrine · 2023

Repeated JWH-018 treatment (6 mg/kg daily for 7 days) induced psychomotor agitation, reduced social dominance and recognition memory, impaired prepulse inhibition, disrupted hippocampal long-term potentiation, decreased BDNF expression, and altered endocannabinoid system components in the striatum and hippocampus, all persisting 15+ days after last exposure..

Trends in Illicit Cannabis Potency based on the Analysis of Law Enforcement Seizures in the Southern Area of Rome.

Vernich, Francesca · 2023

The potency escalation in cannabis isn't just a North American phenomenon.

Brief Report: Suspected Cannabis-Induced Mania and Psychosis in Young Adult Males with Autism Spectrum Disorder.

Al-Soleiti, Majd · 2022

All three patients had ASD and developed mania or psychotic symptoms after consistent cannabis use containing both CBD and THC.

Medical cannabis and cannabidiol: A new harvest for Malawi.

Bandawe, Gama · 2022

CBD has an established role in treating epilepsy (FDA-approved Epidiolex) and emerging evidence for antipsychotic and neuroprotective properties, with the authors proposing potential adjunctive use for neuropsychological complications of malaria..

Cannabis Use in Autism: Reasons for Concern about Risk for Psychosis.

Bortoletto, Riccardo · 2022

Cannabis exposure in autistic individuals may exert disruptive epigenetic effects on brain regions critical to schizophrenia pathophysiology.

Acceptability of cannabidiol in patients with psychosis.

Chesney, Edward · 2022

86% of patients were willing to try CBD.

Understanding the Potential Benefits of Cannabidiol for Patients With Schizophrenia: A Narrative Review.

Dyck, Garrison J B · 2022

Studies suggest CBD may treat multiple symptom domains of schizophrenia: positive symptoms (hallucinations, delusions), negative symptoms (social withdrawal, flat affect), and cognitive deficits.

Young adults with psychosis: Intentions for cannabis reduction and cessation based on theory of planned behavior.

Petros, Ryan · 2022

Participants recognized that cannabis use conflicted with their life goals but maintained use because they perceived it as facilitating social interactions, enjoyable activities, and improved mental health.

Lurasidone use in Cannabis-Induced Psychosis: A Novel Therapeutic Strategy and Clinical Considerations in Four Cases Report.

Ricci, Valerio · 2022

All four patients improved across psychosis symptoms (positive and negative), disruptive behavior, and functional recovery.

White Matter Microstructure and Gray Matter Volume in Cannabis-Induced Psychosis and Schizophrenia With Cannabis Use.

Shah, Raghav · 2022

Participants with schizophrenia and cannabis use (SZC) had widespread white matter microstructural abnormalities, while those with cannabis-induced psychosis (CIP) had fewer WM disruptions and greater gray matter volumes in the cerebellum and frontal regions..

Diagnostic Difficulties and Treatment Challenges of a Young Patient With Severe Acute Psychosis and Complete Recovery.

Siembida, Jagoda · 2022

A young adult presenting with multiple potential contributors to psychosis (cannabis use disorder, excessive vaping, COVID-19 history, pineal cyst, extreme hypertension) achieved complete recovery on haloperidol and a mood stabilizer, highlighting the diagnostic complexity of first-break psychosis..

Changes in Expression of DNA-Methyltransferase and Cannabinoid Receptor mRNAs in Blood Lymphocytes After Acute Cannabis Smoking.

Smith, Robert C · 2022

The 13.4% THC group showed significantly increased CB2 and DNMT3A mRNA levels at 4 hours post-smoking compared to placebo.

Efficacy of Cannabidiol for Δ-9-Tetrahydrocannabinol-Induced Psychotic Symptoms, Schizophrenia, and Cannabis Use Disorders: A Narrative Review.

Bartoli, Francesco · 2021

Across 10 clinical studies, CBD appeared to reduce psychotic-like symptoms triggered by THC in healthy volunteers and positive symptoms in people with schizophrenia.

Epigenetic Mediation of AKT1 rs1130233's Effect on Delta-9-Tetrahydrocannabinol-Induced Medial Temporal Function during Fear Processing.

Blest-Hopley, Grace · 2021

The number of A alleles at AKT1 rs1130233 and methylation percentage at the CpG11-12 site independently predicted greater THC effects on parahippocampal/amygdala activation during fear processing.

THC-induced behavioral stereotypy in zebrafish as a model of psychosis-like behavior.

Dahlén, Amelia · 2021

THC caused dose-dependent behavioral stereotypy (repetitive circular swimming) in adult zebrafish.

Crosstalk between the transcriptional regulation of dopamine D2 and cannabinoid CB1 receptors in schizophrenia: Analyses in patients and in perinatal Δ9-tetrahydrocannabinol-exposed rats.

Di Bartolomeo, Martina · 2021

Perinatal THC exposure increased both Cnr1 (CB1) and Drd2 (D2 receptor) mRNA levels in the adult rat prefrontal cortex, with reduced DNA methylation at the Drd2 regulatory region.

Cognitive performance and lifetime cannabis use in patients with first-episode schizophrenia spectrum disorder.

Hájková, M · 2021

First-episode schizophrenia patients with lifetime cannabis use (n=30) showed better cognitive performance than non-using patients (n=53), with the most prominent difference in visual memory.

Reelin deficiency contributes to long-term behavioral abnormalities induced by chronic adolescent exposure to Δ9-tetrahydrocannabinol in mice.

Iemolo, Attilio · 2021

Heterozygous Reeler mice (reduced Reelin) treated with THC during adolescence showed impaired social behaviors, elevated disinhibitory phenotypes, and increased stress reactivity compared to wild-type mice given the same THC treatment.

Differential Methylation Pattern of Schizophrenia Candidate Genes in Tetrahydrocannabinol-Consuming Treatment-Resistant Schizophrenic Patients Compared to Non-Consumer Patients and Healthy Controls.

Jahn, Kirsten · 2021

In the NRXN1 gene promoter, THC-consuming schizophrenia patients had nearly double the methylation rate compared to non-consuming patients.

Cannabis-Induced Mania Following COVID-19 Self-Medication: A Wake-Up Call to Improve Community Awareness.

Kaggwa, Mark Mohan · 2021

The patient presented with one week of pressured speech, poor sleep, destructiveness, irritability, and altered mental status after two weeks of using homemade remedies including cannabis to treat COVID-19 symptoms.

Cannabidiol Cigarettes as Adjunctive Treatment for Psychotic Disorders - A Randomized, Open-Label Pilot-Study.

Köck, Patrick · 2021

No significant group differences on primary outcomes (PANSS, BDI) after 4 weeks.

Synthetic cannabinoid induced ocular self-injury.

Malik, Kunal · 2021

Both patients had untreated schizophrenia and used K2 (synthetic cannabinoid).

Antipsychotic potential of the type 1 cannabinoid receptor positive allosteric modulator GAT211: preclinical in vitro and in vivo studies.

McElroy, Dan L · 2021

GAT211 dose-dependently reduced locomotor activity, prevented MK-801-induced hyperlocomotion (a model of psychosis), and limited dopamine D2 receptor-mediated ERK phosphorylation in neuronal cells.

Case Report: CBD Cigarettes for Harm Reduction and Adjunctive Therapy in a Patient With Schizophrenia and Substance Use Disorder.

Meyer, Maximilian · 2021

After years of treatment failure with 30 hospitalizations, introducing CBD cigarettes (<1% THC) as adjunctive therapy, combined with off-label methylphenidate, led the patient to report significantly less need for illegal high-THC cannabis.

Clinical Investigation on the Impact of Cannabis Abuse on Thyroid Hormones and Associated Psychiatric Manifestations in the Male Population.

Muzaffar, Anum · 2021

Cannabis-dependent patients showed highly significant differences (P < 0.001) in positive, negative, and general psychopathology scores on the PANSS compared to controls.

Cannabidiol modulation of hippocampal glutamate in early psychosis.

O'Neill, Aisling · 2021

Compared to placebo, CBD produced a significant increase in hippocampal glutamate (p=0.035) and a significantly greater decrease in symptom severity on the PANSS scale (p=0.032).

Normalization of mediotemporal and prefrontal activity, and mediotemporal-striatal connectivity, may underlie antipsychotic effects of cannabidiol in psychosis.

O'Neill, Aisling · 2021

Psychosis patients on placebo showed altered prefrontal activation during verbal encoding and altered mediotemporal and prefrontal activation during recall, along with greater hippocampal-striatal connectivity.

Sociodemographic and clinical profile of cannabis-induced psychosis: A comparative study.

Padhi, Debasish · 2021

Cannabis-using patients with psychosis showed higher scores in pressure of speech, distractible speech, and clanging.

Neurological Soft Signs in Cannabis Use Disorder with or without Psychosis: A Comparative Study from India.

Parmar, Arpit · 2021

Total NES scores were significantly higher in CUD with psychosis (20.53) and CUD without psychosis (15.93) compared to healthy controls (6.20, p<0.001).

Cannabidiol prevents disruptions in sensorimotor gating induced by psychotomimetic drugs that last for 24-h with probable involvement of epigenetic changes in the ventral striatum.

Pedrazzi, João F C · 2021

CBD (30 and 60 mg/kg) attenuated amphetamine- and MK-801-induced disruption of prepulse inhibition, similar to clozapine.

Duration of Untreated Disorder and Cannabis Use: An Observational Study on a Cohort of Young Italian Patients Experiencing Psychotic Experiences and Dissociative Symptoms.

Ricci, Valerio · 2021

Cannabis use did not significantly affect the duration of untreated psychosis (DUP).

Mesolimbic dopamine dysregulation as a signature of information processing deficits imposed by prenatal THC exposure.

Sagheddu, Claudia · 2021

Pre-pubertal male rats exposed prenatally to THC showed reduced population activity of VTA dopamine neurons but more tonically active neurons, enhanced sensitivity to D2 receptor activation by apomorphine, and stress-induced disruption of sensorimotor gating (PPI).

Eye movements in patients in early psychosis with and without a history of cannabis use.

Sami, Musa Basseer · 2021

Among 91 participants across four groups, early psychosis patients without cannabis history had significantly worse smooth pursuit velocity gain compared to those with cannabis history (effect size g=0.76-0.86), suggesting less severe neurobiological alterations in cannabis-associated psychosis..

Do neurocognitive functions in cannabis induced psychosis groups differ from schizophrenia with cannabis use? A controlled cross-sectional study.

Shah, Raghav · 2021

With 20 matched participants per group, cannabis-induced psychosis patients performed significantly better than schizophrenia-with-cannabis patients on general intelligence and attention tests, and showed cognitive deficits only in some executive function domains compared to healthy controls..

Psychiatric Hospitalization and Length of Stay Differences in Cannabis Users and Non-Users with a Primary Discharge Diagnosis of Schizophrenia or Schizoaffective Disorder.

Williams, Steven R · 2021

Cannabis-only users (n=55) had shorter mean hospital stays than non-substance users (n=462): 6.15 vs.

Personality Traits and Psychotic Proneness Among Chronic Synthetic Cannabinoid Users.

Cohen, Koby · 2020

SC users scored higher than natural cannabis users and non-users on neuroticism and schizotypal symptoms (SPQ-B), but lower on agreeableness and extraversion.

The relationship between cannabis use and cognition in people diagnosed with first-episode psychosis.

de Vos, Chloé · 2020

Of 89 FEP patients, 61 (68.5%) were lifetime cannabis users.

Brain Morphology of Cannabis Users With or Without Psychosis: A Pilot MRI Study.

Delvecchio, Giuseppe · 2020

CIP patients showed extensive grey matter decreases in right superior frontal gyrus, precentral, superior temporal gyrus, bilateral insula, right precuneus, right medial occipital gyrus, right fusiform gyrus, and left hippocampus compared to non-psychotic chronic cannabis users.

Cannabis use: A co-existing condition in first-episode bipolar mania patients.

Etyemez, Semra · 2020

Of 15 patients who received urine drug screening, 7 (47%) tested positive for cannabinoids, a rate substantially higher than the general population.

Cannabis use the week before admission to psychiatric in-patient service as a marker of severity.

Madero, S · 2020

Cannabis use the week before psychiatric admission (25.5% prevalence) showed a weak positive correlation with symptom severity (rs=0.28, p=0.03) in bivariate analysis, but was not an independent predictor in multivariate models.

Effects of combined 5-HT2A and cannabinoid receptor modulation on a schizophrenia-related prepulse inhibition deficit in mice.

Marques, Adriana M · 2020

Neither the CB1 agonist WIN 55,212-2 nor the CB1 inverse agonist rimonabant alone affected prepulse inhibition (PPI) or blocked MK-801-induced PPI deficits.

A Little Dab Will Do: A Case of Cannabis-Induced Psychosis.

Rossi, Garrett · 2020

A patient who had used marijuana since age 13 for anxiety without psychotic episodes developed severe paranoid delusions (being watched and followed), insomnia for two weeks, and hypervigilant behavior after switching to "dabbing" (concentrated cannabis with up to 80% THC).

Differential effects of Δ9-tetrahydrocannabinol dosing on correlates of schizophrenia in the sub-chronic PCP rat model.

Seillier, Alexandre · 2020

In PCP-treated rats (schizophrenia model), only the lowest THC dose (0.1 mg/kg) reversed social interaction deficits and normalized elevated anandamide in the nucleus accumbens.

The Potential of Cannabidiol as a Treatment for Psychosis and Addiction: Who Benefits Most? A Systematic Review.

Batalla, Albert · 2019

CBD as monotherapy or adjunct to antipsychotics improved symptoms in schizophrenia patients, with particularly promising effects in early-stage illness.

Cannabidiol (CBD) use in psychiatric disorders: A systematic review.

Bonaccorso, Stefania · 2019

From 1,301 screened papers, 27 met inclusion criteria (RCTs of CBD for psychiatric disorders).

Cannabidiol Counteracts the Psychotropic Side-Effects of Δ-9-Tetrahydrocannabinol in the Ventral Hippocampus through Bidirectional Control of ERK1-2 Phosphorylation.

Hudson, Roger · 2019

Intra-hippocampal THC increased VTA dopamine neuron firing and bursting, decreased GABA frequency, and amplified oscillatory activity via ERK1-2 phosphorylation.

Adolescent Δ9-Tetrahydrocannabinol Exposure and Astrocyte-Specific Genetic Vulnerability Converge on Nuclear Factor-κB-Cyclooxygenase-2 Signaling to Impair Memory in Adulthood.

Jouroukhin, Yan · 2019

Astrocyte-specific expression of DN-DISC1 combined with adolescent THC synergistically impaired recognition memory in adult mice.

Effects of Fatty Acid Amide Hydrolase Inhibitors Acute Administration on the Positive and Cognitive Symptoms of Schizophrenia in Mice.

Kruk-Slomka, Marta · 2019

URB 597 (FAAH inhibitor) at 0.3 mg/kg attenuated MK-801-induced memory impairment, but at 1 mg/kg it worsened it.

Δ9-Tetrahydrocannabinol During Adolescence Attenuates Disruption of Dopamine Function Induced in Rats by Maternal Immune Activation.

Lecca, Salvatore · 2019

Rats exposed to maternal immune activation (MIA) had fewer active dopamine neurons, lower firing rates, and altered activity patterns.

EXTENDED ATTENUATION OF CORTICOSTRIATAL POWER AND COHERENCE AFTER ACUTE EXPOSURE TO VAPOURIZED Δ9 TETRAHYDROCANNABINOL IN RATS.

Nelong, Tapia Foute · 2019

Vaporized THC suppressed gamma power (>32-100 Hz) in the dorsal striatum, orbitofrontal cortex, and prefrontal cortex of rats, with most changes still present a week after a single exposure..

Cannabidiol improves behavioural and neurochemical deficits in adult female offspring of the maternal immune activation (poly I:C) model of neurodevelopmental disorders.

Osborne, Ashleigh L · 2019

Three weeks of CBD treatment (10 mg/kg) restored recognition memory and social interaction in female poly I:C offspring.

Ventral hippocampal overexpression of Cannabinoid Receptor Interacting Protein 1 (CNRIP1) produces a schizophrenia-like phenotype in the rat.

Perez, Stephanie M · 2019

Viral-mediated overexpression of CNRIP1 in the ventral hippocampus caused impairments in latent inhibition and social interaction (behavioral correlates of schizophrenia) and increased dopamine neuron population activity in the ventral tegmental area, a putative marker of psychosis..

Impact of Chronic Cannabis Use on Auditory Mismatch Negativity Generation in Schizophrenia Patients.

Roser, Patrik · 2019

Schizophrenia patients without cannabis use showed reduced frontocentral MMN to duration deviants compared to healthy controls, as expected.

A retrospective study of the role of long-acting injectable antipsychotics in preventing rehospitalization in early psychosis with cannabis use.

Rozin, Emily · 2019

Cannabis users were significantly more dissatisfied with antipsychotic medication (Chi-square 9.67, p < .002) and more likely to be rehospitalized (Chi-square 4.40, p = .036).

Individual factors influencing the duration of untreated psychosis.

Souaiby, Lama · 2019

No single sociodemographic or disease factor predicted duration of untreated psychosis (DUP) individually except education level.

Peripubertal cannabidiol treatment rescues behavioral and neurochemical abnormalities in the MAM model of schizophrenia.

Stark, Tibor · 2019

Peripubertal CBD treatment (30 mg/kg/day from PND 19-39) reversed social interaction deficits and cognitive impairment in MAM rats.

The Endocannabinoid System across Postnatal Development in Transmembrane Domain Neuregulin 1 Mutant Mice.

Chesworth, Rose · 2018

Researchers tracked the development of the endocannabinoid system across eight time points from birth to adulthood in mice carrying a mutation in neuregulin 1 (Nrg1), a known schizophrenia risk gene.

Cannabinoids and glial cells: possible mechanism to understand schizophrenia.

de Almeida, Valéria · 2018

This review examined the intersection of two lines of research: glial cell dysfunction in schizophrenia and the endocannabinoid system's effects on glial cells. Glial cells, which include oligodendrocytes, microglia, and astrocytes, perform essential functions in the brain including myelination, metabolic support, and immune response.

Probing the endocannabinoid system in healthy volunteers: Cannabidiol alters fronto-striatal resting-state connectivity.

Grimm, Oliver · 2018

Researchers conducted a crossover pharmacological fMRI study giving 16 healthy male volunteers placebo, 10mg oral THC, and 600mg oral CBD in separate sessions, then measuring resting-state brain connectivity. CBD significantly increased connectivity between frontal cortex regions and the striatum compared to placebo.

THC exposure of human iPSC neurons impacts genes associated with neuropsychiatric disorders.

Guennewig, Boris · 2018

Researchers exposed neurons derived from human induced pluripotent stem cells (hiPSCs) to THC and analyzed the effects on gene expression. Both acute and chronic THC exposure dampened the neurons' transcriptional response when stimulated with potassium chloride (which mimics neuronal activation).

Chronic cannabis promotes pro-hallucinogenic signaling of 5-HT2A receptors through Akt/mTOR pathway.

Ibarra-Lecue, Inés · 2018

Researchers exposed mice to chronic THC during an early developmental window and then examined serotonin 2A receptor (5-HT2AR) function in the frontal cortex. Chronic THC shifted the receptor toward coupling with inhibitory G-proteins (Gαi1, Gαi3, Gαo, and Gαz) rather than the standard Gαq/11 pathway.

A method to achieve extended cannabis abstinence in cannabis dependent patients with schizophrenia and non-psychiatric controls.

Rabin, Rachel A · 2018

With contingency management incentives and twice-weekly urine monitoring, cannabis-dependent schizophrenia patients achieved abstinence rates statistically similar to controls (42.1% vs 55%, p=0.53).

Medicinal cannabis (Bedrolite) substitution therapy in inpatients with a psychotic disorder and a comorbid cannabis use disorder: A case series.

Schipper, Regi · 2018

The low-THC medicinal cannabis variant Bedrolite was not effective in treating inpatients with psychotic disorders and comorbid cannabis use disorder.

Risperidone versus other antipsychotics for people with severe mental illness and co-occurring substance misuse.

Temmingh, Henk S · 2018

No clear differences between risperidone and clozapine, olanzapine, perphenazine, quetiapine, or ziprasidone on psychotic symptoms, substance use reduction, or study completion in dual diagnosis patients.

Acceptance of pharmaceutical cannabis substitution by cannabis using patients with schizophrenia.

van Amsterdam, Jan · 2018

Both substitute variants (low THC/no CBD and low THC/high CBD) were appreciated by patients.

Understanding marijuana's effects on functional connectivity of the default mode network in patients with schizophrenia and co-occurring cannabis use disorder: A pilot investigation.

Whitfield-Gabrieli, Susan · 2018

At baseline, schizophrenia patients showed DMN hyperconnectivity (correlated with positive symptom severity) and reduced anticorrelation between the DMN and executive control network compared to controls.

The clinical impact of a positive family history of psychosis or mental illness in psychotic and non-psychotic mentally ill adolescents.

Paruk, Saeeda · 2017

Researchers compared 45 adolescents with first-episode early-onset psychosis (EOP) to 45 age- and gender-matched adolescents with non-psychotic mental illness.

Effects of Extended Cannabis Abstinence on Cognitive Outcomes in Cannabis Dependent Patients with Schizophrenia vs Non-Psychiatric Controls.

Rabin, Rachel A · 2017

Nineteen cannabis-dependent patients with schizophrenia and 20 cannabis-dependent controls without psychiatric illness attempted 28 days of cannabis abstinence.

Marijuana and other cannabinoids as a treatment for posttraumatic stress disorder: A literature review

Steenkamp, Maria M. · 2017

The biological case for cannabis helping PTSD was compelling.

A Network Approach to Environmental Impact in Psychotic Disorder: Brief Theoretical Framework.

Isvoranu, Adela-Maria · 2016

This study applied network analysis, a novel mathematical framework, to understand how environmental risk factors relate to psychotic symptoms.

An introduction to the endogenous cannabinoid system

Lu, Hui-Chen · 2016

The endocannabinoid system (ECS) is one of the most widespread signaling networks in the brain.

Long-term hippocampal glutamate synapse and astrocyte dysfunctions underlying the altered phenotype induced by adolescent THC treatment in male rats.

Zamberletti, Erica · 2016

Male rats that received THC during adolescence showed lasting cognitive deficits and psychotic-like behaviors in adulthood, but no emotional disturbances.

Adolescent cannabis exposure interacts with mutant DISC1 to produce impaired adult emotional memory.

Ballinger, Michael D · 2015

Researchers studied mice carrying a mutation in the DISC1 gene (disrupted in schizophrenia 1) to test whether adolescent THC exposure interacts with genetic vulnerability to worsen adult brain function.

Decreased glial reactivity could be involved in the antipsychotic-like effect of cannabidiol.

Gomes, Felipe V · 2015

Researchers used an animal model of schizophrenia based on blocking NMDA receptors (which mimics the glutamate dysfunction seen in schizophrenia) and tested whether CBD could reverse the resulting behavioral and brain changes. Chronic MK-801 treatment impaired social interaction and novel object recognition in mice, modeling the negative symptoms and cognitive deficits of schizophrenia.

Phenomenological subtypes of mania and their relationships with substance use disorders.

Güclü, Oya · 2015

Researchers studied 96 inpatients hospitalized for bipolar manic episodes and identified two clusters of symptoms using factor and cluster analysis.

Prescription stimulant use is associated with earlier onset of psychosis.

Moran, Lauren V · 2015

Among 205 patients recruited from an inpatient psychiatric unit, 40% reported using prescription stimulants (mostly for ADHD) before the onset of psychosis. Those exposed to stimulants developed psychosis at an average age of 20.5 years compared to 24.6 years for unexposed patients.

Clinical correlates of first episode early onset psychosis in KwaZulu-Natal, South Africa.

Paruk, Saeeda · 2015

Researchers assessed 45 adolescents (mean age 15.9) with first-episode psychosis in KwaZulu-Natal, South Africa.

Natural Recovery From Cannabis Use in People With Psychosis: A Qualitative Study.

Rebgetz, Shane · 2015

Researchers interviewed 10 young adults (mean age 23) with early psychosis who had quit cannabis without formal treatment, averaging nearly 8 months of abstinence.

Troubled adolescents: substance abuse and mental disorder in young offenders.

Ribas-Siñol, Maria · 2015

Researchers studied 144 youth seen in a Therapeutic Juvenile Justice Unit in Spain.

Stimulants and Cannabis Use Among a Marginalized Population in British Columbia, Canada: Role of Trauma and Incarceration.

Saddichha, Sahoo · 2015

Researchers compared cannabis and stimulant use patterns among a homeless population in British Columbia, finding distinct profiles for each substance. Cannabis users had notably higher rates of lifetime psychotic disorders (32%).

Cannabis-related episodic memory deficits and hippocampal morphological differences in healthy individuals and schizophrenia subjects.

Smith, Matthew J · 2015

Researchers compared hippocampal shape in four groups: healthy controls (n=44), healthy controls with past cannabis use disorder (n=10), schizophrenia without substance history (n=28), and schizophrenia with past cannabis use disorder (n=15). Both cannabis-using groups showed distinct hippocampal shape differences from their respective non-using counterparts, but the patterns differed.

Cannabis abuse is associated with better emotional memory in schizophrenia: a functional magnetic resonance imaging study.

Bourque, Josiane · 2013

Researchers compared emotional memory and brain activation in three groups: 14 schizophrenia patients with cannabis abuse (dual-diagnosis, DD), 14 non-using schizophrenia patients (SCZ), and 21 healthy controls (HC).

An investigation into "two hit" effects of BDNF deficiency and young-adult cannabinoid receptor stimulation on prepulse inhibition regulation and memory in mice.

Klug, Maren · 2013

Researchers tested a "two-hit" model for schizophrenia vulnerability: BDNF deficiency (genetic hit) combined with chronic young-adult cannabinoid exposure (environmental hit).

Cannabis use and brain structural alterations of the cingulate cortex in early psychosis.

Rapp, Charlotte · 2013

Researchers performed MRI brain scans on 23 first-episode psychosis (FEP) and 37 at-risk mental state (ARMS) patients, manually tracing the cingulate cortex.

Susceptibility of the adolescent brain to cannabinoids: long-term hippocampal effects and relevance to schizophrenia.

Gleason, K A · 2012

Mice received the CB1 agonist WIN55,212-2 during adolescence (postnatal days 30-35) or early adulthood (days 63-70) and were tested after postnatal day 120.

"Spice" and "K2" herbal highs: a case series and systematic review of the clinical effects and biopsychosocial implications of synthetic cannabinoid use in humans.

Gunderson, Erik W · 2012

The researchers conducted a systematic review of published reports on clinical effects of synthetic cannabinoids (SCs) in humans.

An fMRI Study of Neuronal Activation in Schizophrenia Patients with and without Previous Cannabis Use.

Løberg, Else-Marie · 2012

Twenty-six schizophrenia patients were divided into previous cannabis users and never-users and compared during an auditory attention task (dichotic listening) using fMRI.

Cannabis use and schizotypy: the role of social anxiety and other negative affective states.

Najolia, Gina M · 2012

Researchers studied over 650 college undergraduates, comparing those with elevated schizotypy traits to controls.

Alterations of theory of mind network activation in chronic cannabis users.

Roser, Patrik · 2012

Fifteen chronic cannabis users and 14 controls underwent brain imaging while performing a theory of mind task (interpreting cartoon stories that required understanding characters' intentions).

Investigating the interaction between schizotypy, divergent thinking and cannabis use.

Schafer, Gráinne · 2012

Researchers tested 160 cannabis users on two separate days: once sober and once intoxicated.

Pre-illness cannabis use and the early course of nonaffective psychotic disorders: associations with premorbid functioning, the prodrome, and mode of onset of psychosis.

Compton, Michael T · 2011

Researchers examined how pre-illness cannabis use related to the course of early psychosis in 109 first-episode patients. Surprisingly, patients who used cannabis by age 15 had better early adolescent social functioning than those who had not used cannabis.

Does the EQ-5D measure quality of life in schizophrenia?

Halling Hastrup, Lene · 2011

Researchers tested whether the EQ-5D (a widely used generic health measure recommended for economic evaluations) adequately captured quality of life in patients with schizophrenia and cannabis abuse. The EQ-5D showed only moderate correlation with the Manchester Short Assessment of Quality of Life (MANSA), a psychiatric-specific measure (rho = 0.358).

Marijuana-induced mania in a healthy adolescent: a case report.

Iskandar, Joseph W · 2011

An adolescent with no known prior psychiatric history developed manic symptoms following marijuana use.

Effects of the cannabinoid-1 receptor antagonist rimonabant on psychiatric symptoms in overweight people with schizophrenia: a randomized, double-blind, pilot study.

Kelly, Deanna L · 2011

Fifteen overweight patients with schizophrenia on second-generation antipsychotics were randomized to rimonabant (20 mg/day) or placebo for 16 weeks.

Prevalence and psychosocial correlates of prior incarcerations in an urban, predominantly African-American sample of hospitalized patients with first-episode psychosis.

Ramsay, Claire E · 2011

In a sample of 109 patients hospitalized for first-episode psychosis in an urban setting, 57.8% reported previous incarceration.

Implicit and explicit affective associations towards cannabis use in patients with recent-onset schizophrenia and healthy controls.

Dekker, N · 2010

Seventy patients with recent-onset psychotic disorder and 61 healthy controls with varying cannabis use levels were tested on both implicit (automatic) and explicit (conscious) associations toward cannabis. Surprisingly, there were no differences in implicit associations between patients and controls.

Cannabis and psychiatric disorders.

Loga, Slobodan · 2010

The authors identified associations between cannabis use and multiple psychiatric outcomes in young people.

Catechol-O-Methyltransferase (COMT) Val158Met variations and cannabis use in first-episode non-affective psychosis: clinical-onset implications.

Pelayo-Terán, José María · 2010

Researchers examined 169 patients with first-episode schizophrenia spectrum disorders, looking at how the COMT gene (which regulates dopamine) interacted with cannabis use to affect when psychosis first appeared. Cannabis users had significantly earlier onset of psychosis compared to non-users.

The effect of social isolation on rat brain expression of genes associated with endocannabinoid signaling.

Robinson, Stephanie A · 2010

Rats raised in social isolation from weaning to adulthood (a model that produces schizophrenia-like behavioral changes) showed widespread changes in endocannabinoid system gene expression. CB1 receptor mRNA was significantly higher in multiple brain regions of isolated rats, particularly prefrontal areas and cortical layers.

Modulation of mediotemporal and ventrostriatal function in humans by Delta9-tetrahydrocannabinol: a neural basis for the effects of Cannabis sativa on learning and psychosis.

Bhattacharyya, Sagnik · 2009

In a double-blind crossover study, 15 healthy men received 10 mg THC, 600 mg CBD, or placebo before completing a verbal learning task during fMRI scanning. THC increased psychotic symptoms and anxiety while disrupting normal brain activation patterns.

Distinct effects of {delta}9-tetrahydrocannabinol and cannabidiol on neural activation during emotional processing.

Fusar-Poli, Paolo · 2009

Fifteen healthy men received THC (10 mg), CBD (600 mg), or placebo before viewing faces expressing different levels of fear during fMRI scanning. THC increased anxiety, intoxication, sedation, and psychotic symptoms.

Cannabidiol reverses the reduction in social interaction produced by low dose Delta(9)-tetrahydrocannabinol in rats.

Malone, Daniel Thomas · 2009

Pairs of rats were tested in an open field after receiving CBD or vehicle followed by THC or vehicle. Low-dose THC (1 mg/kg) significantly reduced social interaction between rat pairs.

Delta9-Tetrahydrocannabinol-induced cognitive deficits are reversed by olanzapine but not haloperidol in rats.

Egashira, Nobuaki · 2008

Researchers tested whether two different antipsychotic medications could reverse the spatial memory impairment caused by THC in rats using an eight-arm radial maze. THC (6 mg/kg) impaired spatial memory and decreased acetylcholine (ACh) levels in the dorsal hippocampus, a brain region critical for spatial memory. Olanzapine (0.1 mg/kg), an atypical antipsychotic, reversed both the memory deficit and the acetylcholine decrease caused by THC.

The metabolic implications of long term cannabis use in patients with psychosis.

Mushtaq, Farrah · 2008

This narrative review examined how cannabis use might affect metabolic health in people with psychosis, a population already at elevated risk for cardiovascular and metabolic disease. In the general population, cannabis's short-term appetite-stimulating effects through the endocannabinoid system are well documented.

Substance misuse at presentation to an early psychosis program.

Van Mastrigt, Sarah · 2004

Researchers examined the first 357 consecutive admissions to a comprehensive early psychosis program in Canada.

Reduced binocular depth inversion in regular cannabis users.

Semple, David M · 2003

Ten regular cannabis users showed significantly higher scores on the binocular depth inversion illusion (BDII) for inverted images compared to 10 matched controls.

Chronic (-)-delta9-tetrahydrocannabinol treatment induces sensitization to the psychomotor effects of amphetamine in rats.

Gorriti, M A · 1999

Researchers investigated whether chronic cannabis exposure could sensitize the brain to psychosis-like effects, using amphetamine-induced behavior in rats as a model. Three patterns emerged across different exposure conditions.

Investigating medical cannabis for adolescents with Tourette syndrome: tread carefully.

Abi-Jaoude, Elia · 2026

Two feasibility studies of cannabis for adolescent Tourette syndrome readily recruited participants but did not require prior trials of standard evidence-based treatments, raising ethical concerns given cannabis-psychosis associations in youth..

Cannabis Hyperemesis Syndrome: A Psychiatric Approach.

Anibueze, Bibian K · 2026

A young male admitted for drug-induced psychosis developed cyclical vomiting consistent with cannabis hyperemesis syndrome, demonstrating that CHS can coexist with and complicate other cannabis-related psychiatric conditions..

Suicide attempt and paranoia persisting for 28 days following heavy delta-9-tetrahydrocannabinolic acid and tetrahydrocannabinol use: A case report.

Greer, Daniel · 2026

A patient developed paranoia persisting for 28 days following daily consumption of 15-30 mg THC gummies and THC-A in dried plant form, culminating in a suicide attempt — with the patient reporting unfamiliarity with THC-A dosing and its psychoactive potential when heated..

Talking About Cannabis: Perspectives of First Episode Psychosis Care Participants and Parents.

Lucksted, Alicia · 2026

Four themes emerged: Respect for Developing Client Autonomy, 'Good Information' about Cannabis and Its Effects, Good Communication Process, and Conversations Complicated by Changing Norms.

Cannabis use is associated with changes in psychological and functional well-being during young adulthood: evidence from self-reports and hair analyses.

Johnson-Ferguson, Lydia · 2025

In a community sample of 863 young adults, cannabis use at age 20 (measured by both self-report and hair THC) predicted increases in psychotic-like experiences, internalizing symptoms, aggression, problematic substance use, and decreased general well-being from ages 20 to 24.

The impact of recreational cannabis legalization on cannabis-related acute care events among adults with schizophrenia.

Kim, Chungah · 2025

Phase 1 legalization (flower/herbs) was associated with a 25.8% immediate decrease in cannabis-related ED visits among men with schizophrenia (95% CI 13.8-37.6%) and an 18.5% decrease in mental health-related ED visits among women (95% CI 6.0-31.2%).

The impact of schizophrenia genetic load and heavy cannabis use on the risk of psychotic disorder in the EU-GEI case-control and UK Biobank studies.

Austin-Zimmerman, Isabelle · 2024

In the EU-GEI study, daily use of high-potency cannabis had OR 5.09 (95% CI 3.08-8.43) for psychotic disorder even after adjusting for schizophrenia polygenic risk score (PRS).

Psychotomimetic compensation versus sensitization.

Brouwer, Ari · 2024

The authors introduce "psychotomimetic compensation" (short-term symptom relief via endocannabinoid, serotonergic, glutamatergic, and dopaminergic systems) and "psychotomimetic sensitization" (gradual intensification of psychotic-like experiences after repeated drug/stress exposure) to explain how the same drugs can both help and harm..

Assessing Cannabis Use in People with Psychosis.

Chesney, Edward · 2024

Cannabis assessment tools used in psychosis research were originally developed for healthy individuals or people with cannabis use disorder.

New insight in psychotic cannabis withdrawal: case series and brief overview.

Ricci, Valerio · 2024

Four patients referred to a mental health department between 2019 and 2023 developed psychotic features specifically after abrupt cannabis cessation, representing a distinct clinical phenomenon from cannabis-induced psychosis during active use..

Cannabis use and cognitive biases in people with first-episode psychosis and their siblings.

Roldan, L · 2024

Daily and occasional cannabis use were associated with lower odds of speech illusions (OR = 0.605 and 0.646) and jumping to conclusions bias (OR = 0.625 and 0.602) compared to never-use.

Psychopathology and Pattern of Remission of Cannabis-Induced Psychotic Disorder.

Suresh, P N · 2023

Cannabis-induced psychotic disorder presented primarily with positive symptoms (hostility, excitement, grandiosity) and minimal affective symptoms.

Program Evaluation to Aid Choice of Aripiprazole or Risperidone for Hospitalized Adolescents with Cannabis Use Disorder and Psychosis.

Thurstone, Christian · 2023

Adolescents prescribed aripiprazole had a mean length of stay of 5.8 days compared to 9.7 days for risperidone (p=0.002).

A neuropsychological approach to differentiating cannabis-induced and primary psychotic disorders.

Woolridge, Stephanie M · 2023

Cannabis-induced psychosis and primary psychotic disorders may show different neuropsychological profiles despite similar clinical presentations.

Does tobacco dependence worsen cannabis withdrawal in people with and without schizophrenia-spectrum disorders?

Yeap, Zac J S · 2023

Cannabis withdrawal severity was worse in tobacco-dependent individuals compared to non-tobacco-dependent individuals.

The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research

National Academies of Sciences, Engineering, and Medicine · 2017

The most comprehensive cannabis evidence review ever assembled found conclusive evidence for three therapeutic uses (chronic pain, chemotherapy nausea, MS spasticity), substantial evidence for several harms (motor vehicle crashes, lower birth weight, psychosis risk), and insufficient evidence for most other claimed benefits.