Browse more cannabis research, findings, methods, and limitations.
New theoretical framework explains how cannabis and other psychotomimetic drugs can both relieve psychiatric symptoms (compensation) and increase psychosis risk (sensitization) through the same neurotransmitter systems.
Among 353 spine surgery patients, those who tested THC-positive preoperatively consumed more opioids over 90 days than THC-negative patients, with the highest consumption in multi-drug users.
US poison center reports for delta-8, delta-10, and THC-O acetate nearly doubled from 2021 to 2022, reaching 5,022 cases. Children under 6 made up 30% of cases, and 38% had serious outcomes.
European adverse event data on unlicensed CBD products found serious reactions in 18.9% of reports, most commonly liver problems, mental disorders, and worsening epilepsy, predominantly in men using CBD alongside antiepileptic drugs.
Real-world study of 91 adults found CBD showed similar effectiveness for drug-resistant epilepsy whether used for approved conditions or off-label, with clobazam co-prescription strongly predicting who responded.
C. elegans exposed to CBD from early life showed irreversible developmental delays, with purified CBD slightly more toxic than hemp extract, though all adverse doses far exceeded human recommended levels.
Comprehensive review maps cannabinoid drug interactions across epilepsy, cancer, MS, and pain — CYP450 inhibition by CBD and THC can significantly alter blood levels of co-administered medications.
Analysis of cannabis industry testimony in Washington State identified three rhetorical strategies against THC potency regulation: threatening economic harm, distracting from the issue, and discrediting the science, mirroring tactics used by tobacco and alcohol industries.
Legislature-mandated study in Washington found community and professional stakeholders favor THC-based taxation and age restrictions for high-potency cannabis, while industry advocates oppose taxation and prefer education-only approaches.
THC prevented bone marrow cells from becoming macrophages by eliminating reactive oxygen species through two mechanisms, both independent of known cannabinoid receptors, revealing a novel pathway for cannabis-related immune effects.
Prenatal THC exposure impaired spatial memory more severely in adolescent male rats than females, with males losing hippocampal inhibitory interneurons while females gained them, suggesting fundamentally different biological responses.
Among 741 cannabis users, emotion dysregulation was linked to more problematic use in men but less so in women, suggesting cannabis treatment may need sex-tailored approaches to emotional skill building.
Interviews with 75 clinicians and pregnant women in Canada found both groups want open, evidence-based cannabis counseling, but patients reported that real-world clinical encounters consistently fell short.
Survey of 194 regular cannabis users at French music festivals found 63.4% met dependence criteria, with over 40% reporting health or social consequences and higher rates of stimulant and hallucinogen co-use.
Survey of 2,530 California teens found two-thirds noticed substance ads, with cannabis advertising exposure associated with doubled odds of expecting to use marijuana among never-users.
A brief two-session personality-targeted school program reduced cannabis-related harms by 22% over 7 years in high-risk Australian adolescents, though it did not significantly reduce cannabis use itself.
Trauma patients with pre-hospital THC exposure used 2.5 times more opioids during hospitalization than THC-negative patients, though they also had higher injury severity and more co-occurring substance use.
Survey of 69 US hospitals found highly variable breastfeeding policies for cannabis-using mothers, with 16% restricting breastfeeding and no consistent link between policies and state legalization or provider knowledge.
First study to test CBD-CAR T cell interaction found CBD reduced proliferation through apoptosis but preserved cancer-killing function and cytokine secretion, suggesting a complex but not necessarily harmful interaction.
The new 9-item Cannabis Exposure in Pregnancy Tool (CEPT) captures frequency, timing, dose, and mode of prenatal cannabis use with 100% sensitivity and 82% specificity against urine testing.
Rat muscle study found THC worsened alcohol-induced mitochondrial damage, with the most severe effects in young glycolytic muscles, suggesting combined cannabis-alcohol use may be particularly harmful to muscle energy production in younger individuals.
Isolated heart mitochondria from old rats showed nearly double the damage from THC compared to young rats, with alcohol worsening the effect and increasing harmful reactive oxygen species production.
Scoping review of 152 studies found nervous system, psychiatric, and GI effects were the most common cannabis-related adverse events in cancer patients, with significant under-reporting across the literature.
CBD reduced nicotine self-administration in mice without affecting food intake, and attenuated both physical withdrawal symptoms and withdrawal-related pain sensitivity, suggesting potential as a smoking cessation aid.
BRFSS survey of 4,744 adults aged 45+ found non-medical cannabis use associated with 96% lower odds of self-reported cognitive decline, though the extreme effect size likely reflects selection bias rather than a true protective effect.
Review argues that standard cannabis use questionnaires are unreliable in psychosis patients due to symptoms, cognitive deficits, and concealment, recommending quantitative biological measures instead.
Crossover RCT of 46 healthy volunteers found THC inhalation acutely raised anandamide and related lipids, but co-administered CBD at 10-30 mg did not influence these endocannabinoid changes.
Controlled crossover study found THC-containing cannabis impaired 20-minute cycling time trial performance whether smoked or vaped, while CBD-dominant cannabis had no effect on exercise output.
JAMA Pediatrics meta-analysis of 23 RCTs with 3,612 young patients found medical cannabinoids associated with 3x more treatment withdrawals, 5.7x higher liver enzyme elevations, and 2.3x more drowsiness versus placebo.
2022 national survey found 23% of US adults used cannabis, with 30% of users meeting CUD criteria. Over half had co-occurring substance disorders, yet only 16.5% with CUD received any treatment.
Multi-site ED study found cannabis use alone was not linked to higher crash risk, while alcohol alone and alcohol-cannabis combined both increased motor vehicle collision odds, with high cannabis use paradoxically associated with lower crash risk.
Prospective study of 47 CHS patients found droperidol plus diphenhydramine reduced nausea scores from 8.3 to 1.4 and pain from 7.8 to 1.7 within 2 hours, with 12.9% returning to the ED within a week.
Retrospective study of 317 Thai patients with cannabis-induced psychosis found rapid symptom improvement with antipsychotics (primarily risperidone) over 28 days, but 7% were diagnosed with schizophrenia within 1.3 years.
Thai national analysis found geographic overlap between cannabis and TB hospitalizations, with a non-significant 48% higher TB hazard in those with prior cannabis admission, leaving the causal question open.
Thai case-control study found sharing cannabis bongs associated with 4.2x higher TB odds, with a population-attributable fraction (12.2%) nearly equal to tobacco smoking (12.6%), suggesting device sharing is the key risk behavior.
Oregon middle school substance discipline referrals increased 30% after marijuana legalization compared to control states, with dispensary proximity amplifying the effect. High schools showed no significant change.
Among 945 depressed/suicidal youth, 12.7% showed high use of all substances and had the most ADHD, substance use disorders, and suicidality, while 23.8% showed moderate alcohol/nicotine/cannabis use.
Longitudinal study of 381 people found weekly childhood cannabis use and depression independently accelerated DNA methylation aging from adolescence to adulthood, with combined effects equivalent to 3-4 extra years of biological aging.
Growth mixture modeling of 67 cannabis detox patients found two withdrawal patterns: a slow, protracted decline (66%) and a sharp days-2-6 peak followed by rapid improvement (34%), with the peaking pattern linked to lower THC metabolites at admission.
Survey of 5,410 Oklahoma adults found 42% had recent secondhand cannabis smoke exposure, with higher respiratory symptoms especially among those who also used cannabis, and disproportionate exposure among young, minority, and lower-SES populations.
Systematic review of 41 studies reveals the endocannabinoid and stress hormone (HPA) systems interact bidirectionally in psychosis: THC affects stress hormones while childhood trauma alters endocannabinoid signaling.
Longitudinal study of 339 young cannabis users found emotional distress coping motives persistently mediated the link between childhood abuse and problematic use into adulthood, while sleep and pain motives were linked to less problematic use.
JAMA study of 504 pregnant women found nearly half used cannabis, with 58% citing mental health reasons. Those using for mental health had the worst depression scores but no faster improvement than non-users across pregnancy.
RCT of 220 non-treatment-seeking youth found 4 weeks of incentivized abstinence reduced cannabis use and shifted 68% toward reduction goals, with benefits persisting 4 weeks after incentives ended, especially in those without CUD.
Choice experiment with 1,578 adults found cannabis edible preferences driven primarily by package style (33-51%) and health claims (23-31%), with cannabis users preferring youth-appealing designs and warning labels having minimal influence.
Female mice showed greater initial impairment from synthetic cannabinoid AKB48 with higher blood levels and CB1 receptor density, while both sexes developed tolerance by the third dose, with females showing faster brain receptor adaptation.
Meta-analysis of 10 studies and 8,367 participants found cannabis use had no effect on non-medical opioid use during OUD treatment (OR=1.00), challenging policies that require cannabis abstinence for opioid medication access.
Over 57,000 Kaiser Permanente patients in Northern California had suspected CHS ED visits from 2009-2019, with prevalence nearly tripling (175% increase) over the period.
Meta-analysis of 19 RCTs found digital interventions reduced young adult cannabis use by nearly 7 fewer days per month at 3-month follow-up, with personalized feedback being the most common active ingredient across programs.
Clinical trials in 75 volunteers found 800 mg oral CBD raised anandamide 1.6-fold, while combining CBD with THC boosted it to 2.1-fold, revealing a dose threshold and synergistic effect relevant to psychiatric treatment.