Browse more cannabis research, findings, methods, and limitations.
Review of 66 studies concluded cannabis doubles psychosis risk in vulnerable individuals, with dose-response and age-of-first-use effects, and gene-environment interactions modulating individual susceptibility.
Interviews with 24 adults found alcohol led to more social disinhibition and post-sex regret, while marijuana enhanced physical sensations, intensity, and orgasm quality, with both having distinct negative effects on sexuality.
Meta-analysis of 670 epilepsy patients found CBD-rich whole-plant extracts outperformed purified CBD (71% vs 46% improvement) at lower doses (6 vs 25 mg/kg/day) with fewer side effects, supporting the entourage effect.
Largest cannabis GWAS (184,765 people) found 8 significant variants, CADM2 as the top gene, 11% heritability, and Mendelian randomization evidence that schizophrenia risk causally increases cannabis use.
National database analysis found heart attack admissions among cannabis users rose 32% from 2010-2014, with in-hospital mortality up 60%, predominantly in males averaging age 41.
ADHD adolescents with cannabis use disorder had higher hospital costs, longer stays, and 17-fold higher alcohol abuse risk, but received 55% less psychiatric medication and 59% less behavioral therapy.
Study of 247 first-episode psychosis patients found cigarette smoking age, poor childhood academics/sociability, and trauma all predicted heavier premorbid marijuana use before psychosis onset.
Survey of 3,177 LA tenth-graders found high cannabis use across methods (31% combustible, 21% edible, 11% vaporized), with most users consuming via multiple administration methods.
Survey of 455 medical cannabis patients found 1,987 strains available, with preferences highly dispensary-specific and many patients using sativa by day and indica at night.
Retrospective study of 108 children found artisanal CBD oil achieved >50% seizure reduction in 39%, with 10% seizure-free, 14% showing improved alertness, and minimal side effects.
Animal study found THC worsened chemotherapy-induced drops in white blood cells but protected against liver enzyme elevation, suggesting complex drug interactions.
THC during adolescence caused epigenetic changes in rat brains that altered gene activity and led to cognitive deficits - effects not seen with adult exposure. Blocking the changes prevented cognitive harm.
Brain imaging found that schizophrenia-related gray matter reductions were the same whether patients had a history of cannabis/alcohol use or not.
Using incentive-based monitoring, 42% of cannabis-dependent schizophrenia patients achieved 28 days of verified abstinence - statistically similar to the 55% rate in non-psychiatric controls.
Analysis of 405 psychiatric outpatients identified four distinct profiles of co-occurring substance use and mental health symptoms, with cannabis use prominent in three of the four groups.
Boosting the brain's natural cannabinoid 2-AG enhanced fear memory in rats through CB2 receptors and mTOR suppression in the hippocampus - a previously unrecognized pathway.
Ten-year study of 481 street-involved youth found daily cannabis users were 34% less likely to start injecting drugs, challenging the gateway drug hypothesis.
Among 829 hospitalized psychosis patients, those with both cannabis and tobacco use disorders had the highest rates of additional substance use problems, highlighting the need for comprehensive screening.
Review suggests cannabinoids could help manage pain, nausea, appetite loss, and itching in advanced kidney disease patients, but direct evidence in this population remains limited.
Review of preclinical evidence explains how adolescent THC exposure may disrupt the brain's inhibitory GABA system in the prefrontal cortex, potentially triggering schizophrenia-like dopamine dysregulation.
Strong evidence from systematic reviews shows cannabinoids (nabiximols, oral cannabis extract, synthetic THC) are probably effective for MS-related spasticity and pain at doses of 20-40 mg THC daily.
Review explains why standard anti-nausea drugs fail in cannabinoid hyperemesis syndrome and why benzodiazepines, antipsychotics, and topical capsaicin work better, based on the condition's unique pathophysiology.
Review of 137 studies explains that hot showers and capsaicin likely relieve CHS symptoms by activating TRPV1 receptors, which share extensive cross-talk with the endocannabinoid system.
Analysis of employed Americans found medical and recreational cannabis users were more similar than different after controlling for health factors, except medical users were more concentrated in construction and mining.
HIV patients who used cannabis had lower levels of inflammatory monocytes and markers linked to brain inflammation, and THC directly suppressed these markers in lab experiments.
French university students with ADHD (5.6%) had significantly higher rates of cannabis, alcohol, and tobacco use plus behavioral addictions, and were more likely to struggle academically.
Review argues cannabis compounds (THC, CBD, THCA, CBDA, terpenes) show promise for five currently hard-to-treat neurological conditions including Parkinson, Alzheimer, and brain tumors.
CBD has proven benefit for Dravet and Lennox-Gastaut syndromes, and three other cannabinoids (CBDV, THCV, THCA) are in the epilepsy research pipeline.
Seven early-onset Huntington's disease patients showed significant improvement in motor symptoms after cannabinoid treatment, with dystonia scores dropping by 35% and additional benefits in gait, behavior, and weight.
Systematic review of 70 studies (3,000+ patients) found evidence that cannabis-using psychosis patients may have distinct neurobiological profiles from non-using patients, supporting the need for tailored treatments.
Review traces the journey from anecdotal evidence to FDA approval of purified CBD (Epidiolex) for two severe childhood epilepsy syndromes, affecting the roughly one-third of epilepsy patients who are drug-resistant.
First-episode schizophrenia patients who used cannabis gained significantly less weight during 12 months of antipsychotic treatment, with less metabolic deterioration than non-users.
Case series found that substituting street cannabis with a low-THC medicinal cannabis variant was not effective for treating cannabis use disorder in seven psychosis inpatients.
Residential crossover study found dronabinol (oral THC) at 120-240 mg/day significantly reduced cannabis self-administration in daily users, supporting agonist therapy as a potential treatment approach.
Rigorous abuse potential study found CBD showed very low drug-liking even at 6 times the therapeutic dose, and it was significantly lower than alprazolam and dronabinol on all abuse measures.
Review highlights that while CBD treats childhood epilepsy effectively, the endocannabinoid system plays critical roles in brain development, and long-term effects of modulating it in children remain unknown.
Analysis of 29 French CHS cases alongside 113 international cases confirmed a consistent pattern: young male daily cannabis users with cycling vomiting relieved by hot showers but not standard antiemetics.
Meta-analysis of 69 studies found cannabis cognitive deficits are small (d=-0.25) and become non-significant after 72 hours of abstinence — meaning most impairment is residual drug effect, not lasting damage.
Alcohol-dependent animals had depleted endocannabinoid (2-AG) levels in the amygdala, linked to anxiety and excessive drinking. Drugs that boosted 2-AG reversed both effects.
The reasons teens gave for starting cannabis - seeking sedation, stimulation, social acceptance, or recreation - predicted their schizophrenia risk and symptom severity.
Review argues that cannabinoid and glutamate systems converge on disrupted GABA interneuron function, unifying two major models of schizophrenia through their shared effects on theta and gamma brain oscillations.
Smartphone tracking found that 73.5% of young heavy cannabis users lapsed during attempted abstinence, with negative expectations, low family support, and permissive environments predicting relapse.
Translational study in humans and rats showed THC disrupts sensory gating through CB1 receptors by altering theta-band brain oscillations, with CBD failing to prevent these effects.
Review of preclinical evidence shows cannabinoids can kill cancer cells and inhibit tumor growth through multiple mechanisms, but also notes cases of cancer stimulation and the need for clinical trials.
Large cohort study found daily cannabis users had 21% greater odds of staying in opioid treatment (methadone/buprenorphine) over nearly 7 years of follow-up.
After joining New Mexico's medical cannabis program, 34% of chronic pain patients stopped all scheduled prescription medications, with significant monthly decreases across all measures compared to non-enrolled patients.
Meta-analysis of 104 studies (9,958 patients) found cannabinoids provide a statistically significant but clinically small pain reduction (3 mm on a 100 mm scale), with 1 in 6 patients experiencing adverse events.
Systematic review of 36 studies confirmed CBD reduces seizures in treatment-resistant epilepsy (NNT=8 for 50% reduction), with 8.5% achieving complete seizure freedom, though serious adverse events increased.
Chemical analysis of cannabis extracts used by 41 Australian families for childhood epilepsy found wildly inconsistent cannabinoid content, with most samples low in CBD and high in THC, contrary to parents' beliefs.
Experiment found that watching medical cannabis patient testimonials indirectly increased positive attitudes toward recreational cannabis, especially when patients were portrayed as not responsible for their illness.