Marijuana Research Library
THE LATEST PEER-REVIEWED STUDIES AND FEDERAL DATA ON MARIJUANA, IN ONE PLACE
Marijuana research is moving fast, and the industry counts on you not reading it. This library indexes the peer-reviewed studies, federal surveys, and polls SAM tracks for its annual Impact Report, summarized in one sentence each and linked to the primary source. Search it, filter it by topic, and copy a citation.
Mental health
Psychosis, schizophrenia, depression, suicide, and cognition.
Oregon State study: frequent cannabis users wake with more stress hormone in their system
Frequent cannabis users showed elevated waking cortisol levels, countering the industry claim that cannabis relieves stress and anxiety.
JAMA Psychiatry: cannabis use disorder rising sharply among US adults while alcohol use disorder falls
NSDUH analysis of 186,823 adults (Han et al., published Aug 19) found men reporting 2+ CUD symptoms rose from 7.3% to 9.3% and women from 4.5% to 5.6% (2021-2024), with moderate-to-severe CUD up from 3.1% to 4.1% (men) and 1.7% to 2.5% (women) while AUD held flat or fell; steepest rises among adults 35-49 and 50+; NIDA director Nora Volkow: ‘the notion that cannabis is not addictive may basically be incorrect.’
Biological Psychiatry meta-analysis: cannabis users develop psychosis about 2.5 years earlier
UNSW Sydney meta-analysis of 149 studies covering 71,000+ people found cannabis users develop psychotic disorders on average 2.5 years earlier than non-users, with the gap widening by age at onset (1.6 years earlier at ages 20-24, 4.4 at 25-29, 6.3 at 30+); lead author Carly Stevens: ‘no one is really safe when it comes to trying cannabis.’
New Study Reviews the Link Between Marijuana Use and Violence
A multidisciplinary review supports a causal relationship between cannabis use, psychotic disorders, and violence; adolescents 12-19 who regularly used cannabis had an 11.2-fold risk of psychotic disorders and 26.7-fold risk of cases requiring hospitalization.
Cannabis use and glutamate across the psychosis spectrum: in vivo evidence from 7T proton magnetic resonance spectroscopy
7-Tesla brain imaging study (79 participants ages 14-32) found lower anterior cingulate glutamate levels were associated with more severe positive psychotic symptoms specifically in cannabis users, and both cannabis use and glutamate dysfunction independently predicted worse psychotic, depressive, and manic symptoms, a biological mechanism linking cannabis to psychosis risk.
Lancet Psychiatry review (Hall et al.): Regular cannabis use is a contributory cause of psychosis
One of two giant Lancet reviews: ‘credible evidence that regular cannabis use plays a contributory causal role in psychosis,’ with a 2024 meta-analysis finding any recreational use associated with a three-fold increase in psychosis incidence.
The efficacy and safety of cannabinoids for the treatment of mental disorders and substance use disorders: a systematic review and meta-analysis
Meta-analysis of 54 RCTs (2,477 participants, 1980-2025) found medicinal cannabis does NOT effectively treat anxiety, depression, PTSD, psychotic disorders, OCD, or opioid use disorder (no RCTs at all existed for depression); roughly 1 in 7 treated patients had an adverse event beyond placebo rates, and authors warned routine prescribing ‘could be doing more harm than good’ by increasing psychotic symptoms and cannabis use disorder.
Cannabis Use Disorder Among Young People Linked to Diagnosis of Psychiatric Disorders (Johns Hopkins EHR study)
Analysis of ~740,000 US medical records (49,586 patients age 17 and under) found youths with cannabis use disorder had 52% higher risk of subsequent schizophrenia, 30% higher risk of recurrent major depression, and 21% higher risk of anxiety disorders compared with peers with other substance use disorders, suggesting unique vulnerability of the developing adolescent brain.
Relationships between cannabis use and mental disorders: assessing the coherence of evidence from studies with different methodologies
Landmark review in the Lancet Psychiatry cannabis series triangulating epidemiological, genetic, and experimental evidence; concludes the evidence is most coherent for cannabis use increasing risk of psychotic disorders, with risk amplified by adolescent onset, frequent use, and high-potency THC products.
Major Canadian study finds strong link between cannabis, anxiety and depression (McMaster University)
Study of 35,000 Canadians spanning 2012-2022 (bracketing 2018 legalization) found people using cannabis 2+ times weekly were about five times more likely to report anxiety, depression, or suicidality than non-users by 2022, with the cannabis-mental health association strengthening over time and youth suicidality up 44%.
Young-Wolff KC, et al. Adolescent cannabis use and risk of psychotic, bipolar, depressive, and anxiety disorders
463,396 California adolescents followed to age 25: cannabis use linked to 2.19 times the risk of psychotic disorders, 2.01 times bipolar, 34 percent higher depressive, and 24 percent higher anxiety disorders.
Deliberate self-harm and suicide in individuals with cannabis-related hospital contacts in Ontario, Canada
Population study of 11.3 million Ontario residents: people with cannabis-related ED visits or hospitalizations had a 5.4-fold higher risk of deliberate self-harm (aHR 5.35) and a 9.2-fold higher risk of suicide death (aHR 9.22) within 3 years versus the general population; elevated risk persisted (7.2-fold) even after excluding those with diagnosed mental illness.
Myran DT, et al. Changes in incident schizophrenia diagnoses associated with cannabis use disorder after cannabis legalization
Share of new schizophrenia cases attributable to cannabis use disorder in Ontario rose from 3.7 percent before legalization to 10.3 percent after, reaching 18.9 percent among men 19 to 24; 13.6 million residents.
Hsu G, et al. Therapeutic use of cannabis and cannabinoids
“Evidence from randomized clinical trials does not support the use of cannabis or cannabinoids for most conditions” for which they are promoted.
Myran DT, et al. Cannabis use disorder emergency department visits and hospitalizations and 5-year mortality
People who received hospital care for cannabis use disorder had nearly three times the overall mortality and roughly 10 times the risk of death by suicide within five years; 11.6 million residents.
Li S, et al. Cannabis and psychosis: five things to know
People treated in an ER for cannabis-induced psychosis were 241.6 times more likely to develop a schizophrenia-spectrum disorder within three years; any cannabis-related ER visit, 14.3 times; 9.8 million residents.
McDonald AJ, et al. Age-dependent association of cannabis use with risk of psychotic disorder
Teens aged 12 to 19 who used cannabis had 11 times the risk of a psychotic disorder compared with non-users.
Hjorthøj C, et al. Association between cannabis use disorder and schizophrenia stronger in young males than in females
Up to 30 percent of schizophrenia cases among men aged 21 to 30, and about one in five among young men overall, could be prevented by preventing cannabis use disorder; Danish registry of 6.9 million people.
Hjorthøj C, et al. Development over time of the population-attributable risk fraction for cannabis use disorder in schizophrenia in Denmark
Share of schizophrenia cases linked to cannabis use disorder rose from 2 percent in 1995 to 8 percent in 2010, tracking rising potency and use.
Di Forti M, et al. The contribution of cannabis use to variation in the incidence of psychotic disorder across Europe (EU-GEI)
Daily users of high-potency marijuana had “four-times higher odds of psychosis” than never-users (OR 4.8); 11 sites, 901 first-episode psychosis patients, 1,237 controls.
Gobbi G, et al. Association of cannabis use in adolescence and risk of depression, anxiety, and suicidality in young adulthood
Meta-analysis of 11 studies, 23,317 participants: adolescent cannabis use linked to 37 percent higher odds of depression, 50 percent higher odds of suicidal ideation, and 3.46 times the odds of suicide attempt in young adulthood.
Black N, et al. Cannabinoids for the treatment of mental disorders and symptoms of mental disorders: a systematic review and meta-analysis
83 studies: “very little evidence” that cannabinoids improve depressive disorders, anxiety disorders, ADHD, Tourette syndrome, PTSD, or psychosis.
Arendt M, et al. Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders
47.1 percent of patients first treated for cannabis-induced psychosis were later diagnosed with a schizophrenia-spectrum disorder, often more than a year later; 535 cases.
Youth and the developing brain
Adolescent use, addiction, school outcomes, and early-onset risk.
Adolescent Cannabis Use After Cannabis Legalization and the COVID-19 Pandemic (Young-Wolff et al., Kaiser Permanente)
Analysis of 1.3 million pediatric visits (ages 13-17, 2011-2024) in Northern California found teen cannabis use had fallen from 10.4% (2011) to 6.8% (2016), then reversed and climbed to 9.5% by 2018 after California’s 2016 recreational legalization, which researchers tie to shifting risk perceptions, retail availability, lower prices, and vaping products.
New data show marijuana use wrecks academic performance
Teens using marijuana 10+ times per month were almost four times as likely to have poor grades compared to non-users; even any use affected emotional health and academics.
Monitoring the Future 2025 Survey Results
2025 MTF: past-year marijuana use was 8% (8th grade), 16% (10th), and 26% (12th), remaining near historic lows; notably, past-year use of intoxicating hemp-derived cannabinoids such as delta-8 THC reached 2%, 6%, and 9% in 8th, 10th, and 12th grades, a growing unregulated-product exposure among teens.
Chan O, et al. Cannabis use during adolescence and young adulthood and academic achievement: a systematic review and meta-analysis
Adolescent users had twice the odds of dropping out of high school, 39 percent higher odds of lower grades, and 28 percent lower odds of attending university.
Pawar AKS, et al. Systematic review and meta-analysis: medical and recreational cannabis legalization and cannabis use among youth in the United States
Past-month use rose 13 percent among youth (12 to 17) and 22 percent among young adults (18 to 25) in association with recreational legalization.
Sultan RS, et al. Nondisordered cannabis use among US adolescents
Teens with even non-disordered cannabis use had 2 to 4 times the odds of major depression, suicidal ideation, trouble concentrating, truancy, and arrest.
Cerdá M, et al. Association between recreational marijuana legalization in the United States and changes in marijuana use and cannabis use disorder
Cannabis use disorder among 12- to 17-year-olds rose 25 percent in states after recreational legalization.
Meier MH, et al. Persistent cannabis users show neuropsychological decline from childhood to midlife
Dunedin cohort: persistent adolescent-onset users lost an average of 8 IQ points from childhood to adulthood; the points did not return after quitting.
Physical health
Heart, lung, cancer, pregnancy, and other medical harms.
Cannabis use disorder doubles complications after knee surgery
Patients with cannabis use disorder had 119% higher odds of surgical site infection, 114% higher odds of wound complications, and 104% higher odds of an ER visit within 90 days of knee surgery, plus more repeat operations within a year.
Marijuana use disorder linked to massive cancer risk
A study tracking 20 years of records from 67 health systems found heavy cannabis users nearly 4x more likely to develop lung cancer, with the risk persisting after excluding tobacco users.
Cannabinoid hyperemesis syndrome prevalence and risk factors in the U.S
National survey of 10,255 adults found approximately 6% of past-year cannabis consumers reported past-year CHS symptoms; risk was higher with frequent use of edibles and concentrates and riskier use patterns, and did not differ by state legalization status.
18% of daily weed users report CHS symptoms
About 18% of daily cannabis users experience cannabinoid hyperemesis syndrome symptoms, an estimated 7 million U.S. adults (‘scromiting’), with national prevalence near 3%.
7% of pregnant US women report using marijuana; 31% report doctor-recommended use
7% of pregnant U.S. women reported using marijuana, and 31% of current pregnant users said they had a medical recommendation, evidence of a pregnancy-and-marijuana crisis.
Prenatal Cannabis Use and Neonatal Outcomes: A Systematic Review and Meta-Analysis
Updated meta-analysis of 51 publications covering 21.1 million patients found prenatal cannabis use associated with 75% higher odds of low birth weight (OR 1.75; heavy use OR 2.36), 52% higher odds of preterm birth (OR 1.52; heavy use OR 1.95), and 57% higher odds of small-for-gestational-age infants (OR 1.57), with moderate certainty and a dose-dependent pattern.
Cannabis use and risk of testicular germ cell tumour: a systematic review and meta-analysis
Meta-analysis of five studies found current cannabis use associated with 62% higher odds of testicular germ cell tumors (OR 1.62), long-term use (10+ years) with 68% higher odds (OR 1.68), and ever-use with 71% higher odds of non-seminomatous tumors (OR 1.71); authors call cannabis ‘a significant modifiable risk factor’ for testicular cancer.
Cannabis Use and the Risk of Arrhythmias: Insights From a Large Retrospective Multicenter Analysis
In 210,817 cannabis users matched 1:1 to controls, cannabis use was associated with 55% higher risk of atrial fibrillation/flutter (HR 1.55), 79% higher risk of paroxysmal tachycardia (HR 1.79), and a tripled risk of life-threatening ventricular tachycardia/fibrillation (HR 3.08).
Myran DT, et al. Risk of dementia in individuals with emergency department visits or hospitalizations due to cannabis
Adults over 45 who needed hospital care for cannabis had 1.7 times the risk of a dementia diagnosis within five years; such visits rose 26.7-fold among people 65 and older from 2008 to 2021; 6.1 million Ontario adults.
Jeffers AM, et al. Association of cannabis use with cardiovascular outcomes among US adults
Daily marijuana use associated with 25 percent higher odds of heart attack and 42 percent higher odds of stroke, independent of tobacco.
Volkow ND, et al. Adverse health effects of marijuana use
NIDA’s landmark review: marijuana is addictive, impairs the developing brain, and is linked to psychosis, impaired driving, and lung symptoms.
Emergency visits and hospitalizations
Poison control, emergency departments, and cannabis hyperemesis syndrome.
JAMA review: cannabinoid hyperemesis syndrome surging; complete abstinence the only reliable cure
JAMA Insights review (Mayo Clinic/Ohio State authors) concludes ‘the most effective long-term management for CHS is complete abstinence’; cites analysis of 188.6 million ED visits showing CHS-related visits rose from 4.4 to 22.3 per 100,000 (2016-2022), with ~70% of patients male and 35.7% of visits ages 18-25, and flags rising THC potency as a likely driver.
Trends in Emergency Department Visits Involving Cannabis Hyperemesis Syndrome Identified Using a New Diagnosis Code, United States, January 2023-May 2026
CDC identified 199,565 CHS-involved ED visits (Jan 2023-May 2026); after the new ICD-10 code R11.16 took effect Oct 1, 2025, recorded CHS visits jumped 3.7-fold (from 3.35 to 11.26 per 10,000 ED visits), with the highest burden among ages 15-24 (38.7 per 10,000), the first national surveillance snapshot of CHS.
New York State Department of Health report: cannabis-poisoning ER visits surged after legalization
NY DOH data show emergency room visits for cannabis-related poisoning outside New York City jumped 190% from 2016 to 2023, spanning legalization in 2021; the Upstate New York Poison Center logged 569 cannabis cases in the past year, 78% of which required or were referred for healthcare-facility treatment (versus 29% of all poison calls).
2024 Annual Report of the National Poison Data System (NPDS) from America’s Poison Centers: 42nd Annual Report
The 42nd NPDS annual report documented 2,092,689 human poison exposures in 2024, with cases involving moderate, major, or fatal outcomes rising 4.08% per year since 2000; the report is the authoritative national source for tracking pediatric and adult cannabis/THC edible exposure trends for 2024.
Potency, products, and vaping
THC concentration, concentrates, edibles, and vapes.
Cannabis Vaping, Smoking, and Dual Use and the Onset of Respiratory Symptoms Among U.S. Young Adults
PATH Study longitudinal cohort of 5,211 young adults (18-24) found cannabis smoking tripled the odds of new clinically meaningful respiratory symptoms (aOR 3.04), and dual smoking-plus-vaping more than quadrupled them (aOR 4.36) versus non-use.
Compared to low-THC products (10% THC level), 30% THC leads to a 197% increase in THC consumption
Compared with 10%-THC products, use of 30%-THC products led to a 197% increase in THC consumed, users do not self-titrate down when potency rises.
Petrilli K, et al. Association of cannabis potency with mental ill health and addiction: a systematic review
Higher-potency cannabis use is associated with increased risk of cannabis use disorder and psychosis.
Addiction, co-use, and overdose
Cannabis use disorder, withdrawal, and links to other drugs.
Early onset of cannabis use and risk for opioid use disorder across two decades in the United States
National US analysis spanning two decades finding that earlier (adolescent) onset of cannabis use is associated with elevated risk of subsequent opioid use disorder, reinforcing the gateway-risk literature on early initiation and later opioid addiction.
Gilman JM, et al. Effect of medical marijuana card ownership on pain, insomnia, and affective disorder symptoms in adults: a randomized clinical trial
Adults randomly assigned a medical marijuana card had “increased incidence and severity of CUD and resulted in no significant improvement in pain, anxiety, or depressive symptoms.”
Bahji A, et al. Prevalence of cannabis withdrawal symptoms among people with regular or dependent use of cannabinoids
47 studies, 23,518 people: 47 percent of regular users experience cannabis withdrawal syndrome (17 percent in population samples, 54 percent outpatient, 87 percent inpatient).
Hasin DS, et al. Prevalence of marijuana use disorders in the United States between 2001-2002 and 2012-2013
About 30 percent of past-year marijuana users met criteria for a marijuana use disorder; prevalence of use and use disorder roughly doubled over the decade.
Use trends and federal data
National surveys and population-level trends.
WHO issues first cannabis technical brief since 2016: legalization has made marijuana more harmful
WHO’s updated 19-page brief ‘The health and social effects of nonmedical cannabis use’ (dated Aug 25) finds harms ‘most marked in jurisdictions that allow the commercialized supply of cannabis,’ says the psychosis evidence ‘has strengthened’ with cannabis a ‘component cause’ showing dose-response, and cites the 51-study/21.1-million-person pregnancy meta-analysis (low birth weight OR 1.75, preterm birth 1.52, small-for-gestational-age 1.57).
Gallup: US marijuana smoking ties record high at 17%, surpassing cigarette smoking
Gallup (fielded July 1-19): 17% of U.S. adults smoke marijuana, tying the record and more than double 2013’s 7%, versus a record-low 11% who smoke cigarettes; 15% consume edibles and 9% vape; use highest among ages 18-49 (23-25%) and under-$50k households (24%); marijuana users were about twice as likely to drink, undercutting the alcohol-substitution argument.
Monitoring the Future adult panel: marijuana addiction up 97% among middle-aged Americans; record daily use
2025 MTF Panel Study (ages 19-65, released Aug 12): adults 40-50 meeting the disordered-use threshold nearly doubled since 2017 (3.3% to 6.5%, +97%); record daily/near-daily use among adults 19-30 (11.8-12%) and 35-50 (8.5%, up from 6.6% in one year); daily use peaks at ages 27-28 (13.9%); the survey’s first-ever hemp-THC question found 11.4% of adults 19-30 used hemp-derived intoxicants (delta-8/10, HHC) in the past year.
International cannabis policies and their association with cannabis use, cannabis use disorder, and other psychiatric disorders
Companion review in the Lancet Psychiatry cannabis series examining policy liberalization worldwide; finds commercial legalization is associated with increases in adult cannabis use and cannabis-related psychiatric harms including cannabis use disorder, informing the policy-harms debate.
Impaired driving
Crashes, fatalities, and drugged-driving behavior.
Virginia Cannabis Control Authority survey: a third of cannabis-using drivers drive after use at least weekly
Per the CCA’s 2024 driving survey, about one-third of past-three-month drivers who use cannabis reported getting behind the wheel after using at least once a week, and Virginia lacks key tools to catch marijuana-impaired drivers before recreational shops open in 2027.
Hemp-derived intoxicants
Delta-8, THCA, and the Farm Bill loophole.
As much as 80% of hemp-THC products are actually just illegal marijuana
Analysis of hundreds of delta-9 THC edibles sold as federally compliant hemp (collected Oct 2025-Feb 2026) found ~80% would require mathematically impossible compositions to be truly hemp-derived, the median edible would need cannabis material equal to 160% of its non-sugar mass, meaning the THC is likely sourced from marijuana.
Markets, tax revenue, crime, and the workplace
The illicit market, state revenue, and employers.
Quest Diagnostics: one in five American workers tested had a positive hair drug test in 2025, with marijuana driving workplace positivity
Quest Diagnostics’ Drug Testing Index reported July 10, 2026 that 19.1% of workers screened by hair test in 2025 were positive, about one in five, with marijuana the leading drug detected, signaling persistent substance use in the workforce as employers drop THC testing.
Policy, legalization, and Canada
What happened where marijuana was legalized, and the federal picture.
Canadian Journal of Psychiatry: legalization traded reduced crime for increased health harms, 'not good enough'
Leading Canadian researchers concluded (May 2026) that while cannabis offenses fell from ~70,000 (2014) to 8,879 (2024), adult use rose to 26-32%, cannabis-related hospitalizations nearly doubled, 40-60% of past-year users show moderate-to-high risk of problems, and 20-24% of users report driving after use, arguing Canada must impose high-potency restrictions and stronger marketing controls.
Marijuana legalization drove a 10% increase in use over 2016 levels
Marijuana legalization was associated with a 10% increase in use compared to 2016 levels, along with reduced public perception of cannabis risks.
Silver LD, et al. Associations of local cannabis policy and retail availability in Northern California with adverse adolescent mental health outcomes
Teens more than 20 minutes from a marijuana retailer had 47 percent lower prevalence of psychotic disorders than teens within 5 minutes; teens in areas banning storefronts and delivery, 67 percent lower; about 100,000 youth.
Public opinion
Polling on legalization and its effects.
UMass Amherst/WCVB poll: Massachusetts repeal Question 8 trails 33%-55%
Poll of 800 Massachusetts registered voters (fielded Aug. 5-12): 55% oppose the Nov. 3 Question 8 repeal of retail marijuana (40% definitely, 15% probably) versus 33% support with 10% undecided, softer opposition than February's 63%.
Pew Research: 88% of Americans back some form of legal marijuana, but most report negative views of public use
Pew's May 2026 'Key facts about Americans and marijuana' found 88% support medical and/or recreational legalization; the finding lands amid countervailing signals, Gallup's most recent annual survey showed overall legalization support falling to 64%, its lowest since 2019, driven by a 13-point drop among Republicans.
What the industry says, and what the science shows
The most common marketing claims, answered from the studies above.
| Big Marijuana claims | The science shows |
|---|---|
| "Marijuana isn't addictive." | 31 percent of past-year users met the criteria for cannabis use disorder in 2025, 19.3 million Americans. Half of teen users do. 47 percent of regular users experience withdrawal. NIDA's director in 2026: "the notion that cannabis is not addictive may basically be incorrect." |
| "Nobody has ever died from marijuana." | More than 20,000 U.S. deaths from 2000 to 2024 listed marijuana poisoning or a marijuana-related disorder as a cause. People hospitalized for cannabis use disorder face roughly 10 times the suicide risk. One in four Colorado road deaths involves marijuana. |
| "It's natural, so it's safe." | Today's flower averages 16 percent THC and concentrates reach 99 percent; "Woodstock weed" was 1 to 3 percent. Tobacco is natural too. The Lancet Psychiatry in 2026: "There is no universally safe level of cannabis use." |
| "It's medicine." | The FDA has approved cannabinoid medicines that went through trials. Raw marijuana has not passed a single one. A 2026 meta-analysis of 54 randomized trials found cannabinoids do not effectively treat anxiety, depression, PTSD, or psychosis, and increase addiction. |
| "Legalization keeps it away from kids." | Teens in legal states use at higher rates (9.4 vs 6.4 percent), youth cannabis use disorder rose 25 percent after legalization, and pediatric edible exposures rose 1,375 percent from 2017 to 2021. |
| "Legalization kills the black market." | California's illicit market outsells the legal one about three to one and the state seized 63,000 pounds in one quarter of 2026. Oklahoma counts more than 3,000 illegal grows. |
| "Tax revenue will fund schools and roads." | Every $1 of Colorado marijuana tax revenue is associated with about $4.50 in costs. No state has collected more than 1.5 percent of its revenue from marijuana, and receipts are now falling in mature markets. |
| "It's safer than alcohol, and people will switch." | Daily use is linked to 25 percent higher heart attack and 42 percent higher stroke risk and a psychosis risk alcohol does not carry. Gallup in 2026: marijuana users are about twice as likely to drink. |
What the scientists in charge say
"The notion that cannabis is not addictive may basically be incorrect."
Dr. Nora VolkowDirector, National Institute on Drug Abuse, on the August 2026 JAMA Psychiatry findings
"A substantial minority of people who use marijuana will actually develop an addiction to marijuana. That number is significantly higher among youth."
Dr. Vivek Murthy21st U.S. Surgeon General, Senate Finance Committee testimony, 2021
"I don't want anyone to mistake what I'm saying as implying that these products are considered safe for general adult usage."
Dr. Jerome Adams20th U.S. Surgeon General, congressional testimony, 2019
Psychiatry
"There is no universally safe level of cannabis use; thus, the only reliable way to avoid any risk for harm from using cannabis is abstinence."
The Lancet Psychiatry2026 review of cannabis use and mental health outcomes
Portraits: official U.S. government photographs, public domain.
Our selection standard
Every entry links to its primary source: the journal article, the federal dataset, or the government report, never a news aggregator. We include peer-reviewed studies, federal surveys such as NSDUH and Monitoring the Future, and major polls. We summarize each in one sentence using the study’s own framing and association language where the design is observational. Studies with null or mixed findings are noted in our Impact Report; if you think we have missed one, tell us at info@learnaboutsam.org. Marijuana does not need to be rescheduled to be researched: SAM drafted the 2022 Medical Marijuana and Cannabidiol Research Expansion Act, the first stand-alone marijuana law passed by Congress.
Need the full picture? The 2026-27 Impact Report compiles this research with state-by-state data.
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