Browse more cannabis research, findings, methods, and limitations.
Prospective study of 409 infertility patients found current marijuana use doubled the odds of abnormal sperm shape and tripled the odds of low volume, but was unexpectedly associated with better motility.
Multicenter RCT of 169 people with alcohol or cannabis use disorder found that internet-based attentional bias training added to standard treatment produced no improvements in any outcome over 12 months.
Mouse study found females developed tolerance to THC pain relief faster than males in a chemotherapy-induced neuropathic pain model, with effects mediated primarily through CB1 receptors.
Systematic review of 12 studies found that nicotine co-use may mask cannabis-related cognitive deficits in young people, while neuroimaging research on co-use effects remains extremely limited.
National survey of 4,069 veterans found 11.9% cannabis use overall, rising to 24-30% among those with psychiatric conditions, with depression independently tripling CUD risk.
Study of 4,069 veterans found cannabis use disorder was more strongly associated with suicidal ideation and planning than alcohol use disorder alone, independent of psychiatric and trauma factors.
Study of 3,157 veterans found cannabis use and cannabis use disorder were associated with 1.5 to 8.3 times higher odds of psychiatric conditions, suicidality, and treatment utilization.
Danish national registry data showed cannabis-induced psychosis incidence more than doubled from 2006-2016, while alcohol-induced psychosis declined and other substance-induced psychoses remained stable.
Study of 88,637 individuals found genetic risk for schizophrenia did not predict cannabis use disorder, while genetic risk for ADHD did, challenging the shared-genetics hypothesis for the cannabis-schizophrenia link.
Study of 191 cannabis users found blood THC per se limits performed poorly at detecting recent use, with oral fluid THC at 10 ng/mL showing the best but still imperfect performance.
Phase I trial in 12 volunteers found CBD sublingual wafer achieved equivalent blood levels to oil solution and nabiximols spray, with mild drowsiness as the main side effect.
Small crossover trial found vaping 12.5 mg CBD modestly improved verbal memory recall (0.68 additional words) in 34 healthy young adults without affecting attention or working memory.
Systematic review found multiple endocannabinoid system components show anti-inflammatory potential for IBD in preclinical studies, identifying CB1, CB2, FAAH, and MAGL as therapeutic targets.
Case series of 4 patients found olanzapine resolved treatment-refractory cannabinoid hyperemesis syndrome, suggesting a new option for cases not responding to standard treatments.
UK survey found autistic adults were 3.5 times more likely to use CBD than matched non-autistic adults, while reporting significant barriers to seeking cannabinoid-related healthcare support.
Controlled trial of 191 cannabis users found oral fluid THC at 10 ng/mL was the best biomarker for detecting use within 3 hours, outperforming blood measures and showing less bias against frequent users.
Study of 367 college students found using alcohol, marijuana, and nicotine together was associated with over 10 times the odds of impaired driving compared to alcohol use alone.
Mouse study found that acute THC did not affect running preference, performance, or motivation, even though CB1 receptors were necessary for running drive, contradicting popular beliefs about cannabis enhancing exercise.
Italian expanded access program found purified CBD achieved 50%+ seizure reduction in 40% of 82 patients with highly treatment-resistant Dravet or Lennox-Gastaut syndrome who had failed a median of 8 prior drugs.
Mice with reduced Reelin protein showed worse social, behavioral, and stress outcomes after adolescent THC exposure than normal mice, suggesting genetic factors influence cannabis vulnerability.
Study of 50 treatment-resistant schizophrenia patients found THC consumers had nearly double the DNA methylation in the NRXN1 gene promoter compared to non-consumers, suggesting epigenetic links between cannabis and psychosis.
Mendelian randomization found genetic liability to bipolar disorder increased cannabis use risk, but genetic liability to cannabis use did not increase bipolar disorder risk, suggesting a self-medication pathway.
Survey of 1,500 caregivers in Colorado found 11% used marijuana, but 90% of those said their child's pediatrician had never asked about their use.
Large genetic study found cannabis use disorder (but not simply trying cannabis) was robustly associated with schizophrenia risk after controlling for tobacco, with mixed evidence on whether the relationship is causal.
Analysis of over 1 million high school students across 46 states found no evidence that medical marijuana laws or dispensaries increased adolescent marijuana use from 1991-2015.
Scoping review of only 6 studies found cannabis use was mostly not associated with cognitive impairment in bipolar disorder, with two studies finding better performance in some domains.
Hospital review found a 5-fold increase in pediatric cannabis edible exposures after dispensaries opened, with 16% of 32 children needing respiratory support and 34% hospitalized.
Case report of a 52-year-old man with no psychiatric history who developed first-episode mania after self-medicating COVID-19 with cannabis-containing home remedies.
Mouse study found twice-daily adolescent CBD exposure caused no harmful effects on locomotion, anxiety, or spatial memory in adulthood, with a possible learning enhancement.
Rat study found hempseed lipid extract improved cholesterol-related kidney damage more safely than simvastatin, modulating inflammatory pathways and oxidative stress.
National study found emerging adults, men, Black/African American, Native, and sexual minority groups had the highest risk of co-occurring cannabis use disorder and suicidality.
Mouse study found a brain-sparing CB1 receptor blocker reduced weight gain, improved glucose metabolism, and reversed fatty liver without the psychiatric risks that ended rimonabant.
Systematic review of 22 studies found medical cannabis shows promise for fibromyalgia pain, with different THC/CBD ratios affecting different symptoms, though dosing and long-term data remain limited.
Survey of 775 MS patients found 37.5% used cannabis, with users reporting twice the odds of improvement in urinary frequency, urgency, leakage, and bladder emptying.
Community study of 2,142 people found heavy drinking, cannabis use, and stressful events each independently predicted psychosis, with two co-occurring risk factors raising incidence from 1.6% to 17.7%.
Prospective study of 35 children with drug-resistant epilepsy found CBD cut abnormal brain discharges nearly in half and improved sleep microstructure in 85% of those with initial sleep abnormalities.
Small pilot trial of smoked CBD cigarettes for acute psychosis found no significant symptom differences, but the placebo group needed more antipsychotic medication while the CBD group did not.
Lab study found THC reduced glioblastoma cell proliferation through the GPR55 receptor rather than CB1/CB2, and CBD unexpectedly abolished this anti-tumor effect.
Case series of 5 people with FASD found cannabis (mostly CBD) reduced disruptive behavior scores from 18 to 6, suggesting potential for a condition with very few treatment options.
Review of 37 studies found men are twice as likely to have CUD overall, but certain mental illnesses (anxiety, antisocial personality) reverse or narrow the sex gap.
New generation synthetic cannabinoids with alkene modifications showed up to 10x the potency of previous compounds and were found in 25 forensic cases including deaths and impaired driving.
Denmark's medical cannabis pilot found users had higher treatment satisfaction and lower depression but higher pain scores compared to matched controls, showing both benefits and potential harms.
Study of 201 CHS patients found topical capsaicin achieved symptom relief in 55% vs. 21% without, and shortened time to discharge by over 2 hours.
Systematic review of 10 studies found medical cannabis was safe and potentially beneficial for fibromyalgia, with only mild side effects and no serious adverse events.
Survey of 2,841 medical cannabis users found over half used cannabis to replace prescriptions, with 38% stopping and 46% reducing their prescription drug use, primarily pain medications.
Case of a 36-year-old with CHS who developed aortic blood clot and coronary disease requiring surgery because CHS vomiting prevented oral antiplatelet therapy.
Case report of a teenager with multiple substance addictions and depression who improved across all domains after switching from antidepressants to CBD, including quitting all illegal drugs.
Expert panel of 17 developed consensus guidelines for managing cannabis users during surgery, emphasizing screening, potential weaning, extra nausea prevention, and higher pain medication needs.
Review of how endocannabinoids and dopamine work as partners across Maslow's hierarchy — from survival drives to achievement — and how cannabis disrupts that partnership.
Lab study found CBD protected rat brain tissue from simulated stroke damage while THC worsened it, with different receptor mechanisms mediating each effect.