Browse more cannabis research, findings, methods, and limitations.
Prospective study of 4,380 children found maternal cannabis use before (not during) pregnancy predicted higher autism symptoms across childhood, while continued tobacco use during pregnancy predicted autism symptoms at age 6.
Survey of 719 cancer survivors found about one-third used cannabis, with most disclosing to healthcare providers and wanting more information about cannabis.
Longitudinal study of 6,811 Army veterans found cannabis use and other substance use predicted subsequent suicidal ideation and planning, with interactions by sex and depression status.
Large study across four African countries found cannabis and other substance use patterns among people with psychosis varied significantly by country and sex, differing from Western research findings.
Meta-analysis of 13 clinical studies found CBD and THC had trivial, non-significant effects on blood inflammatory markers (IL-6, IL-8, IL-10, TNF-alpha), with evidence certainty ranging from very low to moderate.
CBD reduced brain inflammation and improved neurological outcomes after traumatic brain injury in rats by acting through the PGE2-EP2-cAMP-PKA signaling pathway.
Adolescent THC rerouted dopamine axon growth from the medial to the orbitofrontal prefrontal cortex in male mice, altering impulse control, while females were protected by different molecular responses.
In a 30-person crossover RCT, THC-related simulator crashes peaked 4 hours after inhalation.
In morphine-dependent monkeys, THC modestly reduced some withdrawal signs but was not more effective than existing medication lofexidine, while CBD had no effect alone or combined with THC.
Nationally representative longitudinal study found COVID stay-at-home orders doubled depression odds, but worsening mental health was associated with less marijuana use (78% reduction), contradicting the self-medication hypothesis.
Content analysis found state cannabis regulatory agencies reported stronger public health orientation than alcohol agencies, while alcohol regulators emphasized law enforcement more.
Daily CBD given to young mice from weaning reduced Sertoli cells during spermatogenesis and lowered sperm viability and morphology after 34 days.
Analysis of cannabis-related tweets across continents found political debate was the dominant topic, most personal experiences were positive, and majority sentiment favored legalization.
Meta-analysis of over 10,000 papers found scientific support for medical cannabis in cancer treatment was 31x stronger than opposition, spanning symptom management and potential anticarcinogenic effects.
Breast milk from cannabis-using mothers showed temporarily lower fat levels and blunted lactose increases after use, with THC concentrations correlating with these macronutrient changes.
Pilot study found young adults reported better mood and less anxiety while high, but showed no changes on implicit or explicit emotion regulation tasks.
Multicenter study of 266 patients with 77 different genetic epilepsies found nearly half achieved 50%+ seizure reduction with CBD, with comparable effectiveness between approved and off-label uses.
Mouse study found CBD dampens seizure-like hippocampal activity spread by boosting fast-acting inhibitory PV interneurons through GPR55 receptor signaling.
Economic analysis of 1911-1925 Bengal data found alcohol and cannabis bud were market substitutes, with consumption of both declining as income rose.
Black MSM reported higher cannabis and tobacco use than non-MSM, with path analysis showing cannabis refusal self-efficacy mediated the link between MSM status and tobacco use.
Review of case reports and 9,142 FDA adverse event reports identified potential cannabis-drug interactions in children, particularly involving enzyme inhibition of methadone, everolimus, and antidepressants.
BRFSS analysis found ACEs predicted cannabis use overall, but the link to medical cannabis specifically was fully explained by disability and poor health from childhood adversity.
California spatiotemporal analysis found no link between recreational cannabis outlets and self-harm injuries, while alcohol outlet density was strongly associated with nonfatal self-harm.
Pilot RCT found brain stimulation (HD-tDCS) was safe and feasible for cannabis use disorder with 91.7% completion, but cannabis cue exposure during stimulation did not add benefit.
32-year analysis found cannabis use declined among most US adolescents but not among those with suicidal thoughts or attempts, with female suicide attempters showing a persistent plateau.
Cancer patients had lower baseline endocannabinoid levels, but 30 minutes of moderate exercise boosted endocannabinoids in both cancer patients and healthy controls — along with increased happiness.
Prospective study of 103 children with drug-resistant epilepsy found over half responded to CBD, with sustained seizure and non-seizure benefits and 55% retention at 18 months.
Analysis of 490 hemp-derived intoxicating cannabis vape products found 95 brands selling 26 different compounds, with widespread use of flavors, potency claims, and compliance messaging.
Reddit analysis found cannabis narratives distinctly featured school settings and self-awareness, while alcohol centered on leisure and opioids on healthcare, with recovery strategies varying by readiness stage.
Reddit analysis found people in substance recovery naturally use 11 types of behavior change techniques, with strategies shifting across recovery stages but stigma persisting throughout.
NHANES analysis found former cannabis users had over twice the odds of infertility compared to never-users, while current users showed no elevated risk, with the strongest association among those who quit 3+ years ago.
Mouse study found prenatal THC impaired cognition through CB1 receptors while maternal immune activation worked through CB2 receptors, with the surprising finding that combining both exposures cancelled cognitive deficits.
Study of 252 cannabis users found dabbing produced the highest THC blood levels and strongest intoxication compared to vaping, bongs, and joints, but subjective effects from dabbing and vaping faded faster.
Cannabis users with more positive health expectancies experienced greater acute reductions in tension and pain, suggesting beliefs about cannabis shape therapeutic outcomes alongside pharmacology.
Mouse study found CBD improved treadmill endurance by reshaping gut microbiome; the effect required intact gut bacteria and was reproduced by a single CBD-enriched bacterial species.
Analysis of over 100,000 US adults aged 45+ found past-month marijuana users reported more subjective cognitive decline, with a dose-response relationship between use frequency and cognitive complaints.
Crossover RCT found CBD pre-treatment (1000mg) worsened cannabis-induced memory impairment and psychotic symptoms in 30 patients with schizophrenia, contradicting the protective hypothesis.
An endometriosis cannabis trial aimed for 63 participants but enrolled only 12 and retained 4, primarily because the requirement to abstain from driving was unacceptable.
Smoking THC before exercise raised post-exercise pulse pressure and altered cardiac recovery, but blood pressure and heart performance during exercise were unaffected.
Dunedin Study found persistent cannabis use from ages 18-45 had no significant harmful effects on eye health after accounting for tobacco and socioeconomic status, with one measure suggesting possible neuroprotection.
Living systematic review of 276 studies found most evidence for pediatric cannabinoids is for epilepsy, with CBD showing 30-50% seizure reduction in RCTs.
Among 182 first-episode psychosis patients in South Africa, cannabis use was linked to worse psychotic symptoms across multiple domains, with HIV-positive cannabis users showing additional burden.
ML analysis found different predictors of sustained cannabis vaping by legalization status: cigarette use and bullying in legal states vs heroin use and nicotine vaping in non-legal states.
Single vaporized THC exposure suppressed hippocampal dopamine receptor genes and upregulated glutamate genes in mice, with most recovering within 14 days except persistent Adcy5 downregulation.
Cannabis treatment admissions among US adults 50+ rose substantially over two decades but were proportionally overtaken by other drug admissions, with racial and legal-status disparities.
National survey found 20.6% of cannabis users reported DUI versus 8.6% of alcohol users, with substance disorders, early initiation, and age 65+ as risk factors.
NSDUH analysis found adults 65+ with cannabis use disorder endorsed far fewer diagnostic criteria, especially hazardous use and withdrawal, suggesting potential underdiagnosis.
A 22-year-old daily cannabis user underwent 2 years of inconclusive testing before CHS was diagnosed using Rome IV criteria, with symptoms resolving on cessation and returning on relapse.
Montreal study found the cannabis-nicotine combination had the worst association with anxiety and positive mental health among young adults, while substance count showed no dose-response.
Living meta-analysis of 29 RCTs found THC-containing cannabis produced small pain reductions with large side effect increases, while CBD alone showed no benefit.