Browse more cannabis research, findings, methods, and limitations.
A controlled study found high-potency prenatal cannabis exposure (198 mg THC/day average) reduced birth weight and length, with female newborns showing smaller head circumference.
National survey data found about 5% of pregnant US women used marijuana in the past month, with polysubstance use making marijuana use 2-5 times more likely.
Interviews with 88 Ontario youth, parents, and providers found widespread concern about cannabis harms alongside normalization, with structural barriers hampering harm reduction efforts.
A 10-year follow-up of 192 first-episode psychosis patients found four symptom trajectories, with frequent cannabis use delaying remission and stimulant use triggering relapse.
A study of 4,448 Texas college students found four cannabis-tobacco co-use patterns that remained largely stable over three years, with 42% of students using at least one substance.
A national birth cohort study found later bedtimes and shorter sleep in childhood predicted higher odds of trying marijuana by age 15.
A physician survey found only 10% had authorized medical cannabis, with discussions heavily focused on risks (63%) rather than practical guidance like dosing (6%) or harm reduction (25%).
A case series of 18 incarcerated individuals found drug-soaked paper strips contained synthetic cannabinoids and opioids, causing severe CNS depression, bradycardia, and one death.
Survey of 550 opioid addiction patients found 23% use CBD — primarily for anxiety, pain, and sleep, with 42% using it specifically for withdrawal relief.
Two Phase 1 trials of 83 healthy adults found one week of oral cannabis products reduced a marker of bone resorption, the first human evidence that cannabinoids may affect bone turnover.
A Jamaican national survey found 53% of past-year cannabis users met criteria for severe problematic use, with early start age (before 25) being the strongest predictor.
A cessation trial secondary analysis found that among 500 Black adults, blunt use during a quit attempt did not significantly reduce odds of quitting cigarettes at 12 or 26 weeks.
Analysis of 1,789 urban adolescents identified five distinct substance use patterns, with mental health and perceived drug access differentiating higher from lower risk groups.
National survey data from 2022 found most US cannabis users consumed multiple product types, with consistent patterns between adults and adolescents and correlates varying by route of administration.
Screening of 182 palliative care cancer patients found none met high-risk criteria for drug dependence, suggesting substance use screening may not be warranted in this population.
A 12-week RCT found zolpidem prevented early cannabis withdrawal sleep disturbance but did not significantly increase quit rates (27% vs 15%), with sleep problems returning after medication stopped.
An RCT of 84 adolescent inpatients with cannabis use disorder found mindfulness therapy added to standard care did not improve cannabis outcomes at 6 months, though standard care was effective.
A study of 799 pregnant patients found prenatal cannabis use was associated with 60% higher postpartum depression risk, rising to 62% in those with a history of depression.
Norwegian registry data showed cannabis-induced psychosis declined during COVID while stimulant-induced episodes rose, with recurrent patients more likely to switch between triggering substances.
An fMRI study found first-episode schizophrenia patients with cannabis history had better cognitive control and higher prefrontal brain activity than non-cannabis-using patients.
A pilot RCT of 28 adults with ADHD and cannabis use disorder found extended-release amphetamine significantly reduced cannabis use days but not overall abstinence rates.
Analysis of 299 Israeli news articles found recreational cannabis-impaired driving was framed with individual blame and enforcement, while medical cannabis driving received more sympathetic, educational framing.
Analysis of 4,214 US Epidiolex prescriptions found 40% were off-label (sleep, anxiety, mood, autism), with nearly half of patients co-prescribed interacting benzodiazepines.
A 21-day diary study of 237 college students found co-use of alcohol and cannabis was more pleasurable than cannabis alone, but alcohol appeared to drive the pleasure effect.
Analysis of 299 Jamaican cannabis samples found THC potency surged from 1.1% to 10.2% between 2014-2020, with THC-to-CBD ratios increasing from 2:1 to nearly 200:1.
Survey of 1,006 NJ residents found broader support for spending cannabis tax revenue on health, housing, and education than on policing or courts.
Analysis of 1,466 Instagram posts found cannabis content dominated by advertising, with personal experience stories generating the highest engagement.
Survey of nearly 24,000 students found most teen e-cigarette users wanted to quit or cut back, but fewer were motivated to change their cannabis use.
Survey of 1,547 New England tobacco users found 26% were dual-vaping nicotine and cannabis, with anxiety and male sex as key correlates.
Two-week RCT of 61 Parkinson's patients found no significant motor benefit from high-CBD/low-THC cannabis extract vs. placebo, with possible worsening of cognition and sleep.
Analysis of 4.3-5.7 million VA records (2005-2019) found cannabis use disorder diagnoses rose disproportionately among veterans with psychiatric disorders, especially bipolar and psychotic conditions.
Survey of Fort Worth retailers found Delta-8 THC available at ~10% of licensed locations, concentrated in tobacco and hemp shops, with no decline despite ongoing legal challenges.
Survey of 200 cannabis users found that dependence, emotional dysregulation, and psychopathology predicted other substance use and impaired driving, with no difference between medicinal and black-market users.
Prenatal THC exposure in rats amplified dopamine reward responses and opioid-seeking behavior, with male offspring showing greater vulnerability to relapse.
Among 152 frequent cannabis users, women on hormonal contraceptives showed weaker brain responses to cannabis cues than naturally cycling women or men, pointing to a hormonal mechanism.
An 8-year study found that light cannabis use in late adolescence was associated with conduct problems but not with cognitive decline or changes in reward-related brain activity.
A scoping review found that cannabis exposure alters DNA methylation at genes tied to dopamine signaling, neurodevelopment, and cell survival, with links to psychiatric symptoms.
A study identified four distinct cannabis user profiles and found that rapidly escalating users tried to quit most often, while long-term heavy users had the worst cessation outcomes.
A review found that FDA-approved synthetic cannabinoids dronabinol and nabilone show some analgesic promise but lack strong clinical evidence for pain treatment.
A systematic review found only four studies on recreational cannabis and bone density, with conflicting results.
An MRI study found that people with cannabis use disorder had increased structural brain connectivity in some regions and decreased white matter density in others.
CBD rescued memory deficits in Fragile X model rats through hippocampal GPR55 receptors, pointing to a specific mechanism for cognitive benefits in neurodevelopmental disorders.
A systematic review found THC acutely impairs eye movement control and chronic cannabis users show lasting visual scanning deficits, with potential for roadside impairment testing.
A placebo-controlled trial found that a single dose of a high-CBD medicinal cannabis oil mildly impaired some memory tasks while improving mood in 31 healthy adults.
A woman with a rare genetic epilepsy experienced major improvements in seizures, sleep, mood, language, and motor skills after starting off-label CBD treatment.
A German study found rising THC potency was associated with more cannabis-related psychiatric diagnoses across all 16 federal states, with men affected more than women.
A study found that nearly one-third of Illinois cannabis dispensary social media posts violated advertising regulations in the first year of legal sales.
Lab and animal studies show CBD may protect against Alzheimer's-related neurodegeneration, but no controlled human trials have been conducted.
A study of 18,285 Canadian cannabis users found similar adverse event rates before and after legalization, but ER visits increased while edible-related problems decreased.
A review found that the endocannabinoid system modulates alcohol reward, suggesting cannabinoids could help treat alcohol use disorder, but concurrent use carries additional risks.