Browse more cannabis research, findings, methods, and limitations.
Crossover study of 12 volunteers found oral CBD absorbed much better in oil or nano-emulsion than powder, with nano-emulsion providing the most consistent absorption profile.
Survey of 166 Iranian university students found that personal attitudes and perceived control, not peer pressure, were the strongest predictors of marijuana use intentions.
Largest GWAS meta-analysis of cannabis use disorder (384K participants) identified 22 risk loci, 11% SNP heritability, and strong genetic overlap with ADHD, depression, and schizophrenia.
Longitudinal study of 437 homeless adults in Vancouver found that co-occurring substance use and psychotic disorders were associated with the highest mortality risk over 10 years.
Critical review found moderate evidence for THC:CBD spray (Sativex) reducing MS spasticity and pain, but limited evidence for other MS symptoms.
CB2 inverse agonist Xie2-64 reduced cocaine self-administration and relapse-like behavior in rats without affecting food motivation, suggesting a new approach to cocaine addiction treatment.
Case series of 11 heavy marijuana users who developed small bowel intussusception requiring surgery, with no other identifiable cause in most cases.
Squirrel monkeys learned to discriminate the CB1 antagonist rimonabant from placebo, and THC blocked this discrimination, confirming CB1-mediated subjective effects of cannabinoid blockade.
Small RCT with 14 OCD patients found no significant symptom reduction from acute smoked cannabis (THC or CBD) versus placebo, though CBD showed a trend toward reduced anxiety.
Systematic review of 23 studies found CBD most promising for anxiety and as adjunct treatment for psychosis, with limited evidence for depression and PTSD.
fMRI study of 54 young adults found that those at higher risk for cannabis use disorder showed stronger brain activation in reward regions when exposed to cannabis odor cues.
First Korean study of CBD for childhood epilepsy found about one-third of Lennox-Gastaut and Dravet syndrome patients achieved 50%+ seizure reduction at 3 months, with mostly mild side effects.
Review found early evidence that medical cannabis may help behavioral symptoms in children with autism or fetal alcohol spectrum disorder, and severe nausea in pregnancy, but data remain very limited.
Case series of 30 ICU admissions from synthetic cannabinoid use found one-third presented in coma, 70% needed intubation, and standard drug tests missed the substance in over half of cases.
Systematic review found only four relevant studies and no evidence that chronic cannabis use significantly affects VO2max or physical work capacity.
Focus group of 7 veterans with chronic PTSD found they used medical cannabis for symptom management (especially sleep), not intoxication, with stigma as a major barrier.
Review of 20 years of research found that alcohol produces its addictive brain effects and liver damage largely through the endocannabinoid system, particularly CB1 receptors.
Mouse study found CBD extract significantly induced liver enzymes but the supplement MSM didn't amplify the effect or cause additional toxicity.
Analysis of 7.3 million PCI patients found cannabis users had no worse in-hospital mortality, bleeding, or stroke, and had lower vascular complications compared to non-users.
Systematic review of 41 studies found cannabis use during opioid addiction treatment was mostly unrelated to opioid use, treatment adherence, or retention outcomes.
Canadian national survey of 24,089 people found cannabis use was associated with a weaker link between PTSD and both severe depression and suicidal ideation.
Meta-analysis of two nationwide studies found daily cannabis use associated with 60% higher odds of violence in people with psychotic disorders, though stimulant and depressant use carried higher risks.
Blocking CB1 receptors in mice impaired spatial learning and shifted navigation strategies, with altered brain activity in the hippocampus, striatum, and amygdala.
Systematic review of 25 CBD studies (927 patients) found the best evidence for anxiety and psychosis, with wide dosing variation and generally mild side effects.
Meta-analysis of 3 RCTs (359 patients) found CBD increased 50% seizure reduction by 69% in Dravet syndrome, with notable side effects including somnolence and liver enzyme changes.
Meta-analysis of 4 RCTs (714 patients) showed CBD reduced seizures in Dravet and Lennox-Gastaut syndrome regardless of whether patients were also taking clobazam.
A 21-year-old with no heart disease risk factors had four heart attacks over 18 months, each linked to cannabis use, and became symptom-free after quitting.
Double-blind fMRI study found a single 600mg CBD dose did not alter reward-related brain activity or motivation in 23 healthy volunteers.
Study of 1,010 HIV patients found cannabis use was linked to twice the odds of detectable viral load but no differences in immune cell counts or body weight.
First study to detect THC in human semen, found in 2 of 10 chronic cannabis users with moderate correlation to blood levels. Semen parameters were normal despite heavy use.
Open-label study of 13 Parkinson patients found high-dose CBD improved motor scores by 25% but caused liver enzyme elevations in 38.5% and 85% had diarrhea.
CB1 activation in rats disrupted synchronization between hippocampus and entorhinal cortex, causing time overestimation on a precise timing task.
CB2 agonist JWH-133 reduced bladder pain, inflammation, and urinary frequency in mice with cystitis through an autophagy-dependent mechanism.
Randomized crossover study found co-inhaled high-dose CBD significantly reduced THC systemic availability, with frequent users showing higher levels of both compounds.
Survey of 17,405 cannabis users found men using both medically and recreationally had 40% probability of driving high, versus 20% for women using medically only.
Both CB1 blockade and CB2 activation independently reduced cocaine reward and sensitization in mice, both preventing hippocampal neuronal activation.
Six-week RCT of 65 overweight adults found 15mg daily CBD hemp extract significantly improved HDL cholesterol, with trends toward better sleep and stress coping.
Survey of 973 regular drinkers among Canadian medical cannabis patients found 44% reduced drinking frequency and 8% stopped entirely after starting medical cannabis.
Review found cannabis users may need more sedation and pain medication during surgery, with THC vaping adding respiratory risks from potential lung injury.
fMRI study found cannabis use disorder altered brain connectivity between emotion and stress circuits, with stronger amygdala-hypothalamus signaling correlated to perceived stress.
Rats exposed to cannabinoid agonist during adolescence showed persistent sleep disruption in adulthood, with decreased wakefulness and increased REM sleep.
Study of 106 psychiatric inpatients found 25.5% used cannabis the week before admission, but psychotic diagnosis, not cannabis dose, was the main predictor of symptom severity.
Study of 1,206 young adults found that cannabis dependence, but not recreational use, was associated with a breakdown in normal brain separation between cognitive and emotional processing.
Among 938 young adults with first-episode psychosis, one-third had persistent cannabis use at 1 year with worse symptoms, while those who reduced use showed significant improvement.
Combining a serotonin 5-HT2A blocker with CB1 blocker improved prepulse inhibition in a schizophrenia mouse model, while neither cannabinoid drug worked alone.
Review found prenatal cannabis exposure associated with lower birth weight, neonatal effects, and developmental delays in the first 2 years, with significant research gaps remaining.
Study of 47,447 screened primary care patients found daily cannabis use predicted 24% higher risk of emergency or hospital visits, while other drug use carried even stronger risk.
Review found preclinical evidence for CBD benefits relevant to athletes (pain, inflammation, anxiety), but no studies have directly tested CBD in athletic populations.
Survey of 4,078 Nigerian adolescents found friend drug use, parental smoking, low risk perception, and positive drug beliefs predicted cannabis and illicit drug use.
SAVANT trial subgroup analysis showed nabiximols halved MS spasticity and pain scores consistently across all disability levels, with severe patients showing the most significant gains.