Browse more cannabis research, findings, methods, and limitations.
Using Arizona's random dispensary lottery as a natural experiment, researchers found a ~45% increase in cannabis-related ER visits in zip codes assigned a dispensary, providing unusually strong causal evidence.
In rats, increasing the endocannabinoid 2-AG in the anterior cingulate cortex reduced fear-driven pain suppression via CB2 (not CB1) receptors, revealing an unexpected role for brain CB2 receptors in pain modulation.
Among 503,000+ Ontario births, prenatal cannabis exposure was associated with 51% higher autism diagnosis rate in offspring (HR 1.51), though residual confounding cannot be excluded.
Both activating and blocking cannabinoid receptors during early adolescence impaired sociability in rats, suggesting the endocannabinoid system must be precisely balanced for normal social development. Effects were transient.
A case study and literature review found cannabinoid hyperemesis syndrome is becoming more common as cannabis use increases but remains frequently unrecognized, with no standardized diagnostic or treatment protocols.
A Nature Reviews Neurology article describes the expanded "endocannabinoidome" beyond CB1/CB2 and reviews its involvement in neurological diseases, noting approved therapies for MS and epilepsy and potential applications across neurodegeneration.
CBD reversed the increased pain sensitivity in a mouse model of Parkinson's disease, with effects mediated through CB1 receptors and potentially by increasing endogenous anandamide levels.
A review found purified CBD shows modest but significant seizure improvement in severe epilepsy, but important drug interactions, a 1-in-23 serious adverse event risk, and a wide gap between evidence and public belief complicate clinical use.
Daily cannabis users with sickle cell disease reported worse pain but had nearly 2 fewer annual hospital admissions and similar opioid use compared to matched non-users, suggesting cannabis may help manage pain outside of hospitals.
The cannabinoid agonist HU-210 paradoxically reduced sucrose intake in rats by impairing licking motor mechanics via CB1 receptors, while rimonabant reduced intake through what may be reward devaluation.
A multicenter study of 125 children found slow CBD titration achieved 38% with 50%+ seizure reduction at 6 months with better tolerability than previous faster protocols. Clobazam did not add efficacy but increased some side effects.
Ultra-heavy cannabis users (30,000+ lifetime exposures) from a culture that forbids other substances showed higher schizotypal traits and worse cognitive performance than matched controls, providing unusually clean evidence of cannabis-specific effects.
Non-intoxicated heavy cannabis users showed impaired simulated driving, but only those who started regular use before age 16. Late-onset users performed similarly to non-using controls.
An 8-week pilot trial found guanfacine extended-release was feasible for cannabis use disorder, with significant reductions in use amount and frequency, though only 41% remained in the study.
A review found clear evidence that cannabis affects hippocampal function but weaker evidence for increased striatal dopamine, suggesting the cannabis-psychosis pathway may be more about hippocampal dysfunction than direct dopamine effects.
An Australian study of 55 synthetic cannabinoid deaths found acute toxicity was the top cause but cardiovascular disease was strikingly common in these relatively young decedents, with AB-CHMINACA the most frequently detected compound.
A CB1 receptor positive allosteric modulator unexpectedly antagonized opioid pain relief in the PAG of morphine-withdrawn rats, challenging assumptions about cannabinoid-opioid synergy.
A review found CBD acts on diverse molecular targets including serotonin 5-HT1A receptors, TRPV1 channels, and cannabinoid receptors, explaining its broad therapeutic profile across anxiety, pain, and epilepsy.
A nationwide VA study of 1,413 veterans found cannabis co-use was not associated with meaningful reductions in opioid use or PTSD symptoms, challenging policy rationales for cannabis as a PTSD treatment or opioid substitute.
Prenatal THC exposure selectively destroyed CCK-containing hippocampal interneurons in male but not female mice, causing lasting memory deficits and disrupted brain oscillations through a CB1 receptor-dependent mechanism.
Among 89 first-episode psychosis patients, cannabis users showed no cognitive differences from non-users despite different symptom profiles, with users having more positive and non-users more negative symptoms.
A pilot RCT of 30 CHS patients found topical capsaicin cream significantly reduced nausea at 60 minutes vs. placebo, with 29% achieving complete resolution compared to 0% with placebo.
A pilot MRI study found cannabis users who developed psychosis had widespread grey matter loss in frontal, temporal, and insular regions compared to non-psychotic cannabis users, suggesting psychosis involves brain changes beyond what cannabis use alone produces.
A meta-analysis found only 3 eligible trials (71 patients) testing marijuana for IBD, with no significant benefit over placebo for remission or response and very low quality evidence overall.
A meta-analysis of 4 RCTs confirmed CBD significantly reduces seizures both with and without clobazam, though the effect was somewhat larger with clobazam. Side effects like somnolence were increased with the combination.
Review of why cannabis — an anti-nausea drug — causes severe vomiting in some heavy users. TRPV1 receptors explain the hot shower relief. Cessation is the only cure.
The synthetic cannabinoid JWH-018 produced nausea-like behavior in rats through CB1 receptors, with elevated stress hormones, supporting the theory that cannabinoid hyperemesis syndrome involves stress response dysregulation.
THC-induced nausea in rats was blocked by six different stress-response inhibitors and a benzodiazepine, but not by the standard anti-emetic ondansetron, supporting the hypothesis that CHS is a stress-mediated condition.
A review found THC disrupts neuronal growth factor production through CB1 receptors, with adolescent brains showing different structural and behavioral effects than adult brains, compounded by decades of increasing THC potency.
A leading endocannabinoid researcher describes the expanded endocannabinoidome as a platform for non-psychoactive cannabinoid therapies and highlights its connection to the gut-brain axis in neuropsychiatric disorders.
A previously healthy 28-year-old developed acute respiratory failure from lipoid pneumonia 2 weeks after using a street-bought THC vape cartridge, confirmed by BAL staining and treated with IV corticosteroids.
Specific nicotinic receptor subtypes (alpha3beta4, alpha6beta4) modulated THC withdrawal in mice, with human genetic variants in the same genes associated with cannabis disorder, identifying new medication targets.
A study of 5,000 injured Australian drivers found THC modestly increased crash culpability (OR 1.9) vs. methamphetamine (OR 19), with drug combinations dramatically amplifying risk.
A review of animal models found adolescent cannabis exposure interacted synergistically with early-life maternal deprivation and immune activation to produce schizophrenia-like outcomes, with important sex differences.
Rimonabant-precipitated THC withdrawal in mice significantly reduced motivation for sucrose rewards, modeling the anhedonia of human cannabis withdrawal. A CB1 positive allosteric modulator did not prevent this effect.
Among veterans with cannabis use disorder, 79% had a co-occurring mental health disorder and 77% had another substance use disorder, with comorbid conditions driving greater mental health service use.
Combining cannabis and the anabolic steroid nandrolone in adolescent rats produced synergistic neurotoxicity: worse cognition, more anxiety and aggression, and greater brain damage through oxidative stress and apoptosis.
Mouse study found that the endocannabinoid 2-AG directly blocks virulence programs in gut bacteria by targeting the bacterial receptor QseC, protecting against enteric infections.
Qualitative study found parents of children with drug-resistant epilepsy in Canada face neurologist resistance, lack of insurance coverage, and costs up to $2,000/month when accessing medical cannabis.
Systematic review of 35 studies found cannabidiol likely reduces seizure frequency in children with drug-resistant epilepsy, though it did not achieve seizure freedom more than placebo and increased GI side effects.
Cell study found five cannabinoid agents protected rat brain cells from combined high glucose and amyloid beta damage, with the FAAH inhibitor URB597 showing the strongest neuroprotection.
Prospective study of 214 first-episode psychosis patients found continued cannabis use was associated with increased depression in those with high insight and medication adherence after one year.
Prospective study found 21% of first-episode schizophrenia patients had breakthrough psychosis despite long-acting antipsychotic injections, with cannabis use as an independent predictor.
Cross-sectional study of Canadian students found feeling connected (relatedness) and capable (competence) were linked to less cannabis and alcohol use, while autonomy was linked to more use.
Mouse study found daily low-dose THC reduced endometriosis pain, restored memory, and inhibited endometrial cyst growth, suggesting potential disease-modifying effects beyond symptom relief.
Small retrospective study found 47% of first-episode mania patients who were screened tested positive for cannabis, higher than general population rates.
Matched cohort study of nearly 28,000 people in Ontario found medical cannabis patients had a brief initial increase in healthcare visits that faded over 6 months, with a slight decrease in ED visits.
Analysis of Oregon cannabis found 50 different pesticides, 9 classified as highly hazardous, with medical cannabis containing 3-12 times more residue than recreational products.
Mouse inhalation study found vaporized cannabis (10.3% THC) decreased heart rate and blood pressure while promoting anxiety-like behavior and altering brain activation patterns.
Longitudinal study of 301 young adult cannabis users found self-reported medical use was linked to lower illicit drug use, while concentrate and edible use was linked to higher drug use trajectories.