Browse more cannabis research, findings, methods, and limitations.
Study of 71 hospitalized adolescents found that neither alcohol nor cannabis alone predicted daily self-harm, but using both together on the same day increased self-harm odds by over 30-fold.
In vitro study found CBD selectively suppressed two pro-inflammatory cytokines (IL-1β and IL-6) in human immune cells while leaving 11 other immune signals unaffected, revealing a targeted anti-inflammatory profile.
A 63-year-old with inoperable coronary artery disease and unstable angina unresponsive to morphine experienced pain reduction and improved exercise capacity after starting edible medical cannabis.
Study comparing 20 cannabis-induced psychosis patients to 20 schizophrenia-with-cannabis patients found CIP showed significantly better intelligence and attention, with cognitive deficits limited to some executive function domains.
Analysis of 43 states found legalization and decriminalization dramatically reduced cannabis arrests overall, but racial disparities persisted, with states lacking policy changes seeing increasing racial gaps.
Study found 86.3% of Canadian cannabis companies violated online marketing regulations, with social media platforms showing higher violation rates than websites, particularly for age restrictions and brand glamorization.
Survey of 604 LA young adults found that living near cannabis outlets affected use intentions differently by race/ethnicity, with White young adults near recreational shops showing stronger co-use intentions.
Real-world study of 18 adults with Dravet syndrome found CBD reduced seizures by over 30% in 17.6%, but adverse effects were universal and led to discontinuation in some patients.
Study of 252 endometriosis patients tracking over 16,000 cannabis sessions found inhaled forms more effective for pain while oral forms worked better for mood and GI symptoms.
A young recreational cannabis and tobacco smoker developed dilated cardiomyopathy leading to cardioembolic stroke and peripheral gangrene requiring amputation.
Prospective study of 819 people on opioid therapy found cannabis users were 9% less likely to test positive for fentanyl, suggesting a potential harm-reduction role during the opioid crisis.
Study of 370 involuntary psychiatric patients found THC-positive patients were 2.29 times more likely to be readmitted within a year and more likely to be prescribed benzodiazepines at discharge.
Meta-analysis of 374 animal studies confirmed that cannabinoid receptor agonists consistently reduce pain behaviors, though CBD showed mixed results for inflammatory pain and most studies used only male animals.
Umbrella review found that while many risk factors for substance use disorders were statistically significant, only antisocial behavior had convincing evidence for predicting cannabis use disorder (OR=3.34).
Systematic review of 124 studies found cannabis use in healthy people was linked to adverse effects on psychosis risk, cognition, mood, and functioning, driven by THC content, frequency, and age of onset.
Study found adults with ADHD show different clinical profiles based on substance type: cannabis users had worse general psychopathology, while stimulant/alcohol users showed more hyperactivity and legal problems.
Controlled study found standard field sobriety tests failed to detect cannabis impairment, while a novel app (DRUID) reliably identified it. Blood THC levels returned to baseline before impairment resolved.
PET imaging found women with cannabis use disorder had lower CB1 receptor levels in key brain regions than non-users, while healthy women naturally had higher CB1 levels than healthy men.
Systematic review of 15 studies found marijuana was associated with reduced sperm count, motility, and morphology, though evidence is observational and larger trials are needed.
Systematic review found only 8 small RCTs testing cannabinoids for depression, anxiety, or PTSD, with insufficient evidence to recommend cannabis for any of these conditions.
Prospective study of 361 veterans found sleep problems drove ADHD-related cannabis use, while using cannabis to cope with negative emotions predicted cannabis-related problems.
Study of 404 first-episode psychosis patients found cannabis users were less likely to develop metabolic syndrome, with lower triglycerides and higher HDL cholesterol.
Study of 418 epilepsy patients found artisanal CBD users reported better quality of life, fewer psychiatric symptoms, and reduced healthcare utilization compared to non-users, though seizure control was similar.
Study of 74 young people found cannabis affected brain volume differently by sex (females had more, males had less), while higher aerobic fitness was linked to greater brain volume overall.
Brain tissue analysis found altered cannabinoid receptor expression and distribution in HIV-associated cognitive disorders, with CB1 levels correlating with memory and processing speed deficits.
In UC patients, endocannabinoid levels dropped in the placebo group but remained stable with cannabis treatment, and changes correlated with symptom improvements in bowel movements and quality of life.
Survey of 36,391 women found recreational cannabis legalization was associated with 2.37x higher preconception and 1.51x higher prenatal cannabis use compared to non-legal states.
Study of 124 toxicology patients found 69% of new psychoactive substance cases involved synthetic cannabinoids, with most users primarily seeking to get high rather than avoiding drug tests.
Pilot trial of 77 college cannabis users found that personalized feedback plus text messaging significantly increased perceptions of dangerousness of driving after cannabis use at 3 months.
After Washington legalized recreational cannabis, THC-positive drivers in fatal crashes more than doubled (9.3% to 19.1%), with high-concentration THC drivers increasing nearly five-fold.
Controlled study found the synthetic cannabinoid JWH-018 at a relatively low dose significantly impaired motor coordination, attention, memory, and response speed in 24 cannabis-experienced adults.
Landmark RCT of 224 patients found CBD significantly reduced TSC-associated seizures by about 49%, with the lower dose (25 mg/kg/day) as effective as the higher dose but with fewer side effects.
Fetal brain imaging found prenatal cannabis exposure altered hippocampal connectivity to multiple brain regions, with patterns linked to less favorable outcomes at age 5.
Study of 391 first-time justice-involved youth found emotional dysregulation and positive cannabis expectations predicted cannabis initiation, while self-control was protective.
Randomized trial of 113 at-risk girls found a 12-session trauma-informed intervention (VOICES) significantly reduced cannabis use over 9 months compared to an attention control.
Review of 21 studies found largely inconclusive evidence on whether cannabis laws affect opioid prescribing, use, or mortality, identifying six major research challenges limiting current evidence.
Mendelian randomization found causal pathways from ADHD liability to smoking and cannabis initiation, but not convincingly in reverse, suggesting ADHD drives substance use rather than vice versa.
Review of 86 studies found cannabis use in veterans consistently linked to other substance use, psychiatric disorders, and self-harm, with almost no studies testing therapeutic benefits.
Prospective study of 92 epilepsy patients found 25% developed tolerance to CBD-enriched oil after a mean of 7.3 months, though 54% achieved meaningful seizure reduction overall.
Cardiac arrhythmias among teens hospitalized with cannabis use disorder increased sixfold from 2003 to 2016, with dramatically higher mortality (7.4% vs. 0.1%) and hospital costs when arrhythmia co-occurred.
Analysis of nearly 3,000 suspected impaired drivers in Quebec (2014-2018) found cannabis in 48% of cases, methamphetamine in 54%, and polydrug use in 79%, establishing a pre-legalization baseline.
CB1 receptor blockade with rimonabant reduced atherosclerotic lesions by 64% and improved lipid profiles in lean mice, showing cardiovascular benefits independent of weight loss.
Within-person analysis of nearly 8,000 people over 10 years found cannabis use predicted a sevenfold increase in psychotic experiences, but psychotic experiences did not predict cannabis use, supporting a causal direction.
First clinical description of fatal 4F-MDMB-BINACA intoxication: a 22-year-old died of multi-organ failure 11 days after extensively vaping this synthetic cannabinoid.
PK modeling and adverse event data show cannabis and CBD can increase escitalopram and sertraline levels in adolescents, raising the risk of side effects like dizziness and fatigue.
Cannabis users on buprenorphine maintenance had 2.7x higher drug levels than non-users at the same dose — a significant CYP3A4-mediated drug interaction.
Genetic analysis of 989 ADHD patients and population GWAS data confirmed shared genetic architecture between ADHD and substance use disorders, with evidence ADHD causally increases SUD risk.
Small randomized trial found a nanoparticle CBD oral spray was safe and achieved comparable plasma levels to other formulations, with peak absorption at 60 minutes and no adverse effects.
A 22-year-old with cannabinoid hyperemesis syndrome died after vomiting-induced hypokalemia triggered a fatal cardiac arrhythmia, complicated by QT-prolonging medications and cardiac genetic mutations.
Among 109,308 UK Biobank participants, cannabis use was strongly linked to psychotic experiences, with people in the top fifth of schizophrenia genetic risk showing nearly 10 times the effect size compared to those in the bottom fifth.