Browse more cannabis research, findings, methods, and limitations.
Menopausal mice treated with CBD for 18 weeks had improved blood sugar, bone density, and energy expenditure, along with increased gut Lactobacillus.
ABCD study of ~12,000 children found 1.1% reported cannabis use by ages 12-13, with externalizing behaviors and parental drug problems predicting earlier substance initiation.
Study of 79 young people found cannabis withdrawal symptoms peaked in the first week of monitored abstinence then declined, with mood and sleep most affected.
Review found growing evidence for cannabis-based medicine in Tourette syndrome, with two small RCTs showing THC safety and efficacy for tics, though larger trials are ongoing.
Analysis of 256 cannabis edibles packages found widespread youth-appealing content including candy knockoffs and cartoon characters, with less-regulated states having the most.
Systematic review of 58 CBD trials found consistent anxiolytic effects but highly variable results for psychosis, substance use, and other non-seizure conditions.
Review found smoking marijuana causes chronic bronchitis symptoms but no significant FEV1 decline, and most studies have not linked it to lung cancer.
Quebec cohort study of 2,408 children found no significant association between in-utero cannabis exposure and ADHD risk after adjusting for confounders.
Pilot trial of 97 college students found mobile phone intervention with personalized feedback and text messaging reduced driving after cannabis use over 3 months.
American Heart Association scientific statement concluded marijuana may adversely affect brain health through cognitive impairment and increased stroke risk, especially during neurodevelopment.
Controlled trial in 24 healthy people found a moderate dose of synthetic cannabinoid JWH-018 caused psychedelic effects, dissociation, amnesia, and confusion.
Case report of synthetic cannabinoid user with coumarin contamination causing severe blood clotting disorder, diagnosed rapidly via factor level testing.
A portable potency tester combined with real-time tracking created the first practical standard THC unit measure — higher milligram doses correlated with greater intoxication.
Retrospective study of 114 children with drug-resistant epilepsy found 73% improved with CBD-enriched oil, with 59% achieving over 50% seizure reduction over at least one year.
Diabetic rat study found cannabis reduced sperm motility dose-dependently and lowered testosterone, while metformin increased sperm counts but also reduced testosterone.
Mouse study found delta-8-THC produces tolerance, physical dependence, and abuse-like effects qualitatively similar to delta-9-THC, challenging "milder alternative" marketing.
Rigorous RCT of 136 arthritis patients found synthetic CBD 20-30 mg daily showed no pain benefit over placebo after 12 weeks.
Focus groups with 57 Canadian young adults found they wanted cannabis edibles packaging focused on safe use (standardized dosing, child safety) rather than consumption deterrence.
Australian registry of 3,961 patients found medicinal cannabis was safe and showed sustained improvements in pain, mental health, and insomnia over 2+ years.
Spanish expanded access program of 102 patients found CBD reduced seizures by 48%, with 45% achieving over 50% reduction at 6 months in highly refractory epilepsy.
Scoping review of 163 studies found cancer patients use medical cannabis mainly for nausea, pain, and appetite, with oils as the most common form.
Study of 877 methadone patients found cannabis use shortened treatment retention by 3 years, but this effect was absent in patients with schizophrenia.
Ontario population study of 35,000+ people found cannabis use was not linked to respiratory ER visits but was associated with 22% more all-cause hospitalizations.
Systematic review of 8 RCTs found nabiximols, CBD, and PF-04457845 outperformed dronabinol and nabilone for cannabis use disorder, covering more treatment outcomes.
Survey of 44,119 cannabis consumers found 79-84% of pain users substituted cannabis for opioids, but legalization status made no significant difference.
Three-year Canadian survey found consumers increasingly viewed legal cannabis as safer and more convenient, but price remained the main barrier, especially for frequent users.
Analysis of 9 major cannabis companies found CSR strategies that paralleled tobacco industry tactics, encouraging consumption and targeting marginalized communities.
Colorado study found each increase in dispensary density was associated with 24% more psychosis ER visits after recreational legalization, while schizophrenia visits were unchanged.
Colorado study found cannabis-involved pregnancy hospitalizations more than doubled after legalization, with recreational dispensary density associated with the increase.
Survey of 612 breast cancer patients found 42% used cannabis, mostly during active treatment, with only 39% telling their doctors and half believing cannabis could treat cancer.
Survey of 76 eczema patients found universal support for medical cannabis and 94% interest in learning more, but 93% had never discussed it with their healthcare provider.
Controlled trial of 28 young adults found cannabis mainly affects mood and subjective experience while alcohol primarily impairs cognition and motor performance. Combined effects were additive at most.
Study of 1,099 people with psychotic disorders found those with atypical psychosis had early cannabis use rates (17.5%) closer to schizophrenia (11.5%) than psychotic bipolar disorder (5.3%).
Small study of 18 adolescents found chronic cannabis use linked to DNA methylation changes at six sites that statistically mediated lower verbal memory scores.
Systematic review of 23 studies (917 participants) found most high-quality evidence suggests medical cannabis has minor cognitive effects at low to moderate THC doses.
Mouse study found four synthetic cannabinoids caused convulsions that were not true brain seizures on EEG, suggesting standard anti-seizure drugs like diazepam may be ineffective.
Systematic review of 65 studies found medical cannabis legalization associated with fewer fatal crashes while recreational legalization associated with more, with both increasing cannabis-positive driver tests.
Pilot trial of 52 young adults found emotion-focused therapy outperformed standard CBT for reducing emotional distress in cannabis use disorder, with both treatments reducing cannabis use.
Study of 451 Latinx college students found attachment style, marianismo beliefs, and bicultural self-efficacy shaped the link between childhood adversity and substance use among women.
Mouse study found THC weakened PD-1 immunotherapy by suppressing T-cell function through the CB2 receptor. In human cancer patients, higher endocannabinoid levels were linked to worse survival.
Study of 2,293 adolescents found parent disapproval directly reduced cannabis use while peer disapproval worked through changing risk perception, with similar patterns in legalized and non-legalized states.
Review of 16 studies found marijuana use associated with increased risk of heart attack within 24 hours and stroke, especially in people with existing cardiovascular conditions.
A 32-year-old man developed progressive bilateral vision loss and unusual black optic disc pigmentation after two years of synthetic cannabinoid (bonsai) use, a previously unreported finding.
Mouse study found cannabis extracts reduced gut inflammation better than pure THC or CBD alone, with each treatment producing a distinct immune response pattern.
London study of 2,130 catatonic episodes found 5.1% were substance-related, with cannabis the most frequently implicated substance. Cases increased between 2007 and 2016.
Focus groups with 53 pregnant cannabis users found legalization reduced access barriers and stigma, and that participants trusted cannabis retailers as information sources.
Study of 99,127 pregnancies found prenatal cannabis use was more common near cannabis retailers (6.8% pre-pandemic, 8.2% during), with the pandemic increase larger for those within 10 minutes of a store.
Lab study found synthetic cannabinoids targeting either CB1 or CB2 receptors reduced brain immune cell inflammation and protected neurons from secondary damage via MAPK suppression.
NYC survey found 30.7% of families experienced marijuana smoke incursions during the pandemic, with families in subsidized housing facing nearly 7 times the odds and their children having 3 times the asthma rate.
Scoping review of animal studies found cannabinoid exposure during brain development (prenatal, adolescent) caused lasting cognitive harm, while exposure in old age showed potential cognitive benefits.