Browse more cannabis research, findings, methods, and limitations.
Latent class analysis of 15,429 U.S. postpartum women identified seven substance use patterns, including 5.5% who used cannabis before pregnancy but largely stopped during.
Meta-analysis found people with autism had significantly lower blood anandamide levels, and animal models showed reduced brain endocannabinoids, with symptom improvement when levels were raised.
Meta-analysis of 31 studies found cannabis use associated with 55% higher fatal crash risk and doubled injury crash risk, with low certainty evidence per GRADE.
Global Burden of Disease analysis (1990-2021) shows cannabis use disorder is the most prevalent drug use disorder worldwide, with burden concentrated in high-income countries.
In a rat PTSD model, CBD did not significantly reduce anxiety but improved spatial memory and reduced brain oxidative stress, suggesting neuroprotective rather than directly anxiolytic effects.
Longitudinal study using both self-report and hair THC analysis found cannabis use at 20 predicted increased psychotic-like experiences, worse mental health, and poorer functioning at 24.
In 62,000 Americans, the link between cannabis and psychotic-like experiences disappeared after accounting for methamphetamine, cigarette, and opioid use.
Lab analysis of 80 CBD products found all contained CBDV, most contained CBG, CBC, CBN, and CBDA at widely varying concentrations not disclosed on labels.
Proof-of-concept with a single OUD patient found vaped cannabis dose-dependently reduced naloxone-precipitated withdrawal scores from 22 to 14 without dangerous vital sign changes.
Denver Health data showed youth psychosis hospitalizations rose significantly after cannabis legalization, with CUD-involved cases quadrupling from 2.0 to 8.5 per 100,000 monthly.
After Florida legalized smokable medical cannabis, weekly THC dispensed per patient increased 42% and continued rising, exceeding recommended daily dose thresholds.
Study of 400 young adults found rural participants had lower subjective social status, with a mediation pathway through emotion dysregulation to hazardous cannabis use.
fMRI study found women cannabis users had blunted brain responses to cannabis cues compared to men, with unique brain-craving links found only in women.
ABCD study found light physical activity (measured by Fitbit) reduced odds of substance use initiation by 26% in adolescents, while moderate and vigorous activity had no significant effect.
National survey found cannabis use disorder nearly quadrupled suicidal ideation risk in women veterans, while lifetime cannabis use doubled suicide plan odds.
Swiss survey found 3.8% of pregnant women used CBD products and 7.6% used tobacco, but only 25% of tobacco users received cessation counseling.
Swiss study found pregnant women using cocaine/opioids had nearly 4x higher odds of adverse newborn outcomes compared to cannabis-only users.
National analysis found 15.2% of adults using opioids and/or cannabis co-used both, with co-users being younger, poorer, and more psychologically distressed than single-substance users.
Six months of daily THC during adolescence in monkeys produced persistent brain connectivity changes in reward regions and lasting motivational deficits into adulthood.
The American College of Physicians issued best practice advice telling clinicians to discuss cannabis benefits and harms with chronic pain patients, while identifying youth, pregnant patients, those with substance use disorders, and frail patients as groups where harms likely outweigh benefits.
A survey of 80 elite Canadian athletes found 38% had used CBD, with most reporting benefits for sleep (93%) and relaxation (90%). Anti-doping violation concerns were the top barrier to use.
Self-identified autistic adults using a tracking app reported an average 73% reduction in symptom severity after cannabis use, with more severe symptoms showing greater improvement and no dose escalation over time.
A Swedish cohort study of 3,328 adolescents found those with higher-SES parents were more likely to use cannabis, with low-SES teens showing 39% lower risk of past-year use after adjustment.
A meta-analysis of 109 studies across 32 countries found 29.2% lifetime cannabis prevalence among medical students, with rates rebounding to 30.4% in the 2020s after declining from the 1970s through 2000s.
A phase 3 trial of 820 adults in Nature Medicine found full-spectrum cannabis extract VER-01 significantly reduced chronic low back pain vs. placebo, with effects sustained over 12 months and no dependence signals.
A woman developed brain damage from thiamine deficiency after 8 weeks of uncontrolled vomiting caused by cannabinoid hyperemesis syndrome—but recovered rapidly with treatment.
About 30% of epilepsy patients resist standard drugs—and the evidence for CBD and THC as anticonvulsants keeps growing, though access remains limited.
Most young vapers want help quitting, but there's no consensus on how—and 40% also vape cannabis, which they see as less harmful than nicotine.
In rats trained to recognize THC, THCV partially mimicked THC at moderate doses (54.6% substitution) but blocked THC effects at higher doses, with an inverted U-shaped response pattern.
An open-label trial of 11 girls with Rett syndrome found a low-THC cannabis extract improved communication, eye contact, attention, anxiety, and quality of life over 12 weeks.
Young adults with cannabis use disorder showed significant drops in heart rate variability and increased heart rate immediately after smoking, measured by wearable smartwatches over 3 days.
In 211 ER encounters for cannabinoid hyperemesis syndrome, droperidol was associated with 24% shorter stays, fewer medications, and 84% lower odds of opioid use, with only 2 mild adverse reactions.
A systematic review of 32 studies found cannabinoids often outperformed outdated antiemetics and placebo for chemo nausea, but only one study compared them to modern standard-of-care treatment.
Analysis of 5,586 cannabis retailers across 18 states found those in neighborhoods with higher deprivation and more low-income residents of color had 2.0-2.5 times the odds of retailer presence.
Washington state counties with more cannabis stores per capita had 17% lower accidental poisoning and opioid death rates from 2009-2020, with no increase in motor vehicle, suicide, or homicide mortality.
Among 847 people with MS, the 30% who used cannabis performed significantly worse on processing speed and working memory tests, even after adjusting for disease severity and other factors.
Among 4,285 veterans with heart disease, cannabis smoking was linked to higher rates of heart attack, stroke, and cardiovascular death—though confounders remain.
A prospective survey of 129 long-term medical cannabis users for chronic musculoskeletal pain found 93% reported symptom improvement, 72% had no cognitive effects, and 80% maintained stable usage over time.
TMS measurements showed cannabis users had increased cortical excitability, reduced intracortical inhibition, and delayed motor inhibition compared to controls, with changes correlating to addiction severity.
A study of 1,058 young Danish men found no association between ever using cannabis and semen quality or most reproductive hormones, though a slight FSH increase suggested possible early testicular effects.
Among 22,763 cancer patients, cannabis dependence showed no association with mortality, while alcohol and opioid dependence were significant predictors of death even after adjusting for tumor stage.
An analysis of 121,061 Ontario schizophrenia patients found cannabis legalization was associated with a 26% decrease in cannabis-related ER visits for men and an 18.5% decrease in mental health ER visits for women.
A longitudinal sibling study found early-onset cannabis use was the strongest predictor of arrest, probation, and incarceration by age 18, outperforming childhood ADHD, oppositional behavior, and anxiety/depression.
CBG suppressed key inflammatory markers and pathways (MAPK, NF-kB) in cell cultures and a mouse model, though physical inflammation reduction in mice was not statistically significant.
CBD blocked metastasis-promoting EMT in pancreatic cancer cells by inhibiting the lncRNA MALAT1 and PI3K/Akt/mTOR signaling, and synergized with gemcitabine chemotherapy in 3D tumor models.
Analysis of 7,635 young adult cannabis users across 23 states found 57% used two or more consumption methods, with recreational legalization and e-cigarette co-use among the strongest predictors.
A genome-environment study of 212 infant deaths found prenatal cannabis use associated with 3.7x higher SUID risk, strengthening to 6.0x after removing cases with genetic explanations.
In 4,808 adolescents, genetic predisposition to sensation seeking predicted early substance and alcohol use by age 15, while no impulsivity-related genetic scores predicted cannabis initiation specifically.
A placebo-controlled trial of 36 youth with alcohol use disorder found single-dose 600mg CBD had no effect on brain chemistry, alcohol cue-reactivity, cravings, or drinking behavior.
First meta-analysis of brain spectroscopy studies found cannabis users had lower GABA and neural health markers in the anterior cingulate cortex, and lower glutamate in the basal ganglia.