Browse more cannabis research, findings, methods, and limitations.
Long-term study found CBD reduced seizures by 45-87% through nearly 3 years in 140 patients with treatment-resistant focal epilepsies, regardless of epilepsy type.
British Journal of Psychiatry editorial argues cannabis policy should reduce psychosis harm while improving access to regulated medicinal products.
Animal study found prenatal cannabinoid exposure impaired breathing reflexes and cardiovascular responses in juvenile rats, with sex-specific effects.
THC impaired verbal memory as expected, but adding CBD in a 1:1 ratio didn't protect against the effect—challenging a popular harm reduction claim.
Comprehensive review finds cannabis use linked to heart rhythm disturbances, especially atrial fibrillation in young males, with synthetic cannabinoids posing even higher risk.
Italian 10-year study found people with cannabis use disorder had 22 times the suicide attempt rate of the general population, highest among women and those with co-occurring psychiatric diagnoses.
Review highlights that Native American communities face unique cannabis policy challenges, with higher youth use rates and multi-jurisdictional regulatory complexity.
Study of 471 college students found eating disorder symptoms linked to cannabis use disorder, with male students showing the strongest association.
Single-dose CBD reversed social deficits, repetitive behaviors, and cognitive problems in a mouse autism model, though it did not affect stereotyped movements.
PET imaging in Alzheimer's mice showed the brain's cannabinoid system changes early in disease, with sex-dependent patterns that could guide treatment approaches.
THC was detected in 12.4% of crash victims—nearly as common as alcohol—and unlike alcohol, drivers weren't less likely to test positive than passengers.
Small trial of mindfulness-based therapy for cannabis users showed better adherence and trends toward more durable reduction, but differences did not reach statistical significance.
Review finds cannabinoid hyperemesis syndrome, causing severe vomiting in chronic cannabis users, is increasingly diagnosed in emergency departments and frequently misidentified.
Rat study found activating cannabinoid receptors during adolescence worsened ADHD-like hyperactivity and risk-taking, with stronger effects in females.
Analysis of 25,000 relevant tweets found mostly positive public sentiment about CBD for insomnia, though clinical trial evidence remains limited.
Cannabinoid receptor activation reduced impulsive decision-making specifically in highly impulsive rats, with effects lasting at least two weeks after the last dose.
Scoping review of 29 studies found CBD shows promise for both anxiety and sleep, but inconsistent methods and dosing across studies limit definitive conclusions.
Study of 2,303 diverse young adults found race- and gender-based discrimination linked to worse cannabis use outcomes but fewer alcohol problems.
Ontario data showed cannabis involvement in PTSD emergency visits rose 151% during cannabis liberalization (2008-2022), outpacing alcohol's 58% increase.
Survey of 243 caregivers found CBD with clobazam improved seizures (87%), cognition (84%), and communication (76-81%) in patients with severe epilepsy.
In 107 patients with severe epilepsy syndromes, 69% achieved at least 50% seizure reduction with CBD—with genetic causes and LGS/TSC showing the best outcomes.
CBD fights seizures through multiple mechanisms including neuroinflammation reduction, modulation of several receptor systems, and oxidative stress reduction.
Analysis of 17 state cannabis policy areas from 2002-2019 found more restrictive policies consistently associated with lower cannabis use in both adults and youth.
Small RCT found CBD 300 mg/day significantly reduced behavioral symptoms of vascular dementia after 4 weeks without cognitive or functional side effects.
Analysis of 35 impaired driving cases found THC levels sometimes rose at later blood draws, showing the difficulty of determining when cannabis was last used.
Rat study found THC exposure at different pregnancy timepoints produced different effects on brain immune cells and social behavior—timing matters, not just exposure.
Rat study found prenatal THC exposure during early vs late pregnancy produced opposite effects on brain immune cell activity and social behavior.
Systematic review found youth cannabis use shaped by multi-level factors: individual perceived risk, peer influence, neighborhood stress, and policy context.
Daily tracking of 65 young adults found social/environmental triggers drove cannabis use more than emotional states, challenging self-medication theories.
Review finds CHS is increasingly diagnosed in teenagers, with diagnostic delays and ineffective standard treatments highlighting the need for greater pediatric awareness.
Pilot study found strong demand for cannabis use disorder treatment among MS patients, with over half using cannabis and up to 20% at risk for use disorder.
Pilot RCT found telehealth brain stimulation with mindfulness reduced cannabis use by 1.4 days/week and significantly decreased withdrawal in women with MS.
Neonatal rat study found CBD significantly enhanced phenobarbital's antiseizure effects, supporting potential combination therapy for newborn seizures.
Study found cannabis co-users smoked more cigarettes when asked to switch to alternatives and were less likely to attempt tobacco cessation.
Small RCT found cannabis oil significantly improved hunger scores in systemic sclerosis patients with wasting, with trends toward better appetite, weight, and quality of life, though most results did not reach statistical significance.
Culturally adapted prevention program improved emotional skills and shifted cannabis habits among Polynesian adolescents, with strongest effects in non-users and low-users.
Large prospective study found ongoing cannabis use beyond the first trimester was linked to 60% higher odds of depressive symptoms later in pregnancy, while any-use overall was not significant.
Large prospective cohort found no significant link between prenatal cannabis use and child cognitive, motor, or language development at age 2, with an unexpected positive language association in girls.
Analysis of 698 adverse reaction reports since Canadian cannabis legalization found most came from older medical users of extracts, with different side effect profiles for THC- and CBD-dominant products.
Low-dose THC given daily for three weeks improved wound healing in old mice by coordinating immune cell responses and reducing inflammation at the wound site.
Across 25 African countries, 3.4% of school-going adolescents used marijuana, with bullying, school skipping, and sadness consistently predicting substance use regardless of substance type.
In 63 older adults with HIV, higher cannabis use was linked to reduced gut microbial diversity and dose-dependent decreases in Dialister, a bacterium important for mucosal health.
Systematic review found strong animal evidence that prenatal cannabinoid exposure disrupts brain neurotransmitter systems, but identified a critical lack of human studies on this topic.
Among 3,050 New Zealand drunk drivers, 27% also tested positive for cannabis and 16% for prescription medications, revealing widespread poly-substance use among impaired drivers.
Systematic review applying Hill causality criteria found cannabis likely contributes to schizophrenia development (OR 2.88), with adolescent use carrying roughly double the risk.
Cancer survivors in pain were more likely to use cannabis and cigarettes but less likely to drink—suggesting pain drives specific self-medication choices.
Prospective study of 150 young lung cancer patients found 39% smoked both cannabis and tobacco, with dual smokers showing more aggressive cancers and emphysema than tobacco-only smokers.
Combined CBD and sodium nitroprusside during early brain development prevented schizophrenia-like symptoms in rats, with stronger effects in females than males.
Systematic review organized cannabis harm reduction strategies into a three-part typology covering legal, socio-organizational, and health-related interventions across multiple countries.
Among 508,025 Ontario children, prenatal cannabis exposure was linked to fewer primary care visits but more ER visits, hospitalizations, and psychiatrist visits through age 10.