Browse more cannabis research, findings, methods, and limitations.
Among 297,620 veterans on opioids, cannabis use did not reduce mortality. In adults 65+ on long-term opioids, cannabis was associated with 55% higher 90-day mortality.
After 30 years of research, only two formal medical cannabis indications are supported by evidence: CBD for rare childhood epilepsy and CBD/THC for MS spasticity.
Beyond relieving MS symptoms, cannabinoids and ECS modulators may promote oligodendrocyte survival and myelination, suggesting potential disease-modifying effects.
In Uruguay, registered cannabis self-cultivators were associated with more traffic crashes, while pharmacy purchases and cannabis clubs showed no consistent link.
Adding pictures to cannabis warning labels significantly improved health risk recall and perceived effectiveness among 523 at-risk young adults.
CBD reduced seizures by 50%+ in 27% of 41 children with severe epilepsy, but quality of life and adaptive behavior did not improve over six months.
Anxiety was the top reason for medical cannabis use among 207 Pennsylvania patients, with 95% reporting no side effects and more than half reporting improvement.
ADB-BUTINACA emerged in 10 UK emergency patients since 2021, causing reduced consciousness in all cases, including two from contaminated edible "cannabis" gummies.
Among 5,738 African American male students, disliking school and believing most peers used marijuana were the strongest predictors of past-year use.
Only 16 controlled studies exist for CBD in psychiatric disorders. Most promising evidence for psychosis and anxiety, but not enough for clinical recommendations in any condition.
Young adults with bipolar disorder showed a unique brain response to stress that correlated with less cannabis use and better depression outcomes over one year.
Among 256 pregnant patients, continued cannabis use through delivery was linked to 10% lower birthweight, and mothers with higher childhood trauma scores were more likely to keep using.
Legal cannabis cultivation in Colorado caused 67+ hectares of land use change and vegetation clearing, including in threatened species habitats.
A 2-hour cannabis education module improved NP test scores by 39%, with 92% reporting willingness to discuss cannabis with patients at 3-month follow-up.
Among 1,527 people who use illicit opioids in Vancouver, 22% intentionally used other substances to reduce opioid use, with cannabis being the second most common substitute at 28%.
In 246 first-episode psychosis patients, 78% had used cannabis, with 94% starting use years before psychotic symptoms. Earlier exposure predicted worse outcomes.
Parental cannabis use was the strongest predictor of teen use among 839 Slovenian students, with mothers' parenting style and specific cannabis rules also playing key roles.
Cannabis products showed minimal to no benefit for sleep disorders in this review, and cannabis withdrawal itself causes significant insomnia that can drive relapse.
Most evidence supports cannabis for pain, but no head-to-head comparison exists between preparations. The entourage effect lacks systematic support for pain.
Edible gummies were seen as healthier and more appealing than other cannabis forms. Health claims on packages boosted positive feelings, while health warnings had little effect.
Study characterized actual medical cannabis product purchases in New York State, providing rare objective data on patient product selection in a regulated market.
Young adults who newly adopted an LGBQ+ identity had 2.9x the risk of starting cannabis use, suggesting identity transition is a vulnerable period.
Following 701 people from age 10 to 22, high social anxiety trajectories predicted adult cannabis use (but not alcohol) along with dramatically elevated mental health disorder risk.
CBD has multiple properties relevant to opioid withdrawal management and is safe with opioids, but large clinical trials are needed before it can be recommended as an adjunct treatment.
First meta-analysis finds fibromyalgia patients have altered levels of endocannabinoid-like molecules, supporting endocannabinoid system involvement in chronic widespread pain.
Among 1,472 bladder cancer patients, marijuana use (25%) was not linked to recurrence, while tobacco smoking duration strongly predicted cancer return.
Topical 20% CBD oil resolved both biopsy-confirmed squamous cell carcinoma and lichen simplex chronicus on a 64-year-old woman's hands.
Cannabis users showed worse verbal memory than controls, but adolescent users (16-17) were not more impaired than adult users (26-29), challenging the adolescent vulnerability hypothesis.
Adolescent THC exposure caused lasting, sex-specific hippocampal damage in rodents, with females more severely affected through disrupted estrogen-endocannabinoid signaling.
Analysis of an online pregnancy forum found cannabis-using mothers primarily seek information about drug testing, CPS involvement, and state-specific legal consequences rather than health effects.
The largest retrospective study of capsaicin cream for cannabinoid hyperemesis syndrome found modest pain relief and that 42% of patients needed no additional treatment afterward.
Daily THC during adolescence disrupted brain immune cell (microglia) function in mice through young adulthood, impairing responses to infection and stress. Effects were adolescent-specific and eventually resolved.
Brain imaging found adults with childhood ADHD who used cannabis had weaker thalamus-parietal connections than non-users, while non-users had stronger-than-typical connectivity in these regions.
UK Biobank analysis found cannabis lowered eye pressure but was associated with glaucoma diagnosis about 10 years earlier in heavy users, challenging the idea that cannabis protects against glaucoma.
UK Biobank analysis found cannabis users developed cataracts 4-5 years earlier than non-users, independent of cigarette smoking, though overall cataract risk was not increased.
UK Biobank analysis found marijuana use associated with 15.6% lower heart attack incidence, comparable to the protective effect of moderate red wine consumption.
UK Biobank genetic analysis found cannabis lowers eye pressure through the GAS7 gene in humans, while the receptors responsible in mice (CB1, GPR18) are not involved in people.
Population survey found adults using both marijuana and e-cigarettes were 12 times more likely to be under 30 and had elevated rates of poor mental health, respiratory conditions, and cigarette smoking.
Lab testing of 25 high-THC cannabis extracts found huge variation in anti-cancer and anti-inflammatory effects, with specific terpenes like terpinene and p-cymene predicting better outcomes.
Systematic review found 61-95.5% of women reported pain relief from cannabis for gynecologic conditions, and PEA-combination studies showed a 3.35-point pain reduction, but inconsistent formulations limit conclusions.
The largest neuroimaging review of adolescent cannabis use (90 studies, 9,441 participants) found evidence of altered brain structure and function in frontoparietal, frontolimbic, frontostriatal, and cerebellar regions.
Review described how edible cannabis products pose unique pediatric risks due to food-like appearance, copycat packaging, lack of smell, and delayed onset that promotes overconsumption.
Mouse study identified CB2 cannabinoid receptors in skin immune cells as the mechanism for suppressing chemotherapy-induced nerve pain, working through a peripheral pathway that avoids psychoactive effects.
A three-year follow-up of 1,689 adolescents found that even low-level alcohol use in the emergency department predicted nearly double the odds of developing cannabis use disorder.
Researchers proposed a "cannabinoid hypothesis" of schizophrenia describing multiple biological pathways through which THC may trigger psychosis, paralleling established dopamine and serotonin hypotheses.
Comprehensive review found cannabis exposure linked to adverse effects across reproductive health: altered fertility, preterm birth, impaired fetal development, and THC present in breast milk.
Review found the best evidence for treating pediatric cannabinoid hyperemesis syndrome is IV rehydration plus haloperidol 0.05 mg/kg, with cannabis cessation as the only long-term cure.
Review identified the TRPV1 ion channel as the common mechanism behind both cannabis pain relief and cannabinoid hyperemesis syndrome, explaining why capsaicin and hot showers treat CHS.
Study of 1.28 million Canadian births found prenatal cannabis use nearly doubled the risk of preterm birth and low birth weight and increased congenital anomaly risk by 71%, with female infants more susceptible.
Longitudinal brain imaging of 724 adolescents found combined alcohol and cannabis use accelerated gray matter decline in five brain regions, with neither substance alone producing the same effect.