Summary: A large longitudinal study of more than 460,000 adolescents shows that even occasional cannabis use during the teenage years is linked to a substantially higher risk of developing serious psychiatric disorders. Participants tracked from ages 13 through 26 who reported past-year cannabis use were about twice as likely to be diagnosed with psychotic or bipolar disorders.
With potency of cannabis products rising in recent years, the research found that psychiatric diagnoses most often appeared within about two years of the first recorded report of use, and the increased risk persisted after accounting for prior mental health history and socioeconomic factors.
Key Facts
- Double the Risk: Any self-reported past-year cannabis use between ages 13 and 17 was associated with roughly a 100% increase in the risk of incident psychotic and bipolar disorders.
- Typical Onset Window: Psychiatric diagnoses generally followed the initial report of cannabis use by an average of 1.7 to 2.3 years.
- Higher Potency Concern: Researchers emphasize that contemporary cannabis products are much stronger than those of prior decades—flower often exceeds 20% THC and concentrates can reach very high THC levels.
- Large Sample: The study followed 463,396 adolescents over a multi-year period, strengthening the validity of its findings.
- Risk Is Broad: The link between adolescent cannabis use and later psychiatric diagnoses remained significant even after adjusting for other substance use and earlier psychiatric conditions.
Source: Public Health Institute
Overview: A major new study published in JAMA Health Forum reports that adolescents who used cannabis had notably higher rates of clinician-diagnosed psychotic, bipolar, depressive, and anxiety disorders by young adulthood. The association was strongest for psychotic and bipolar disorders.
The cohort included 463,396 teenagers aged 13 to 17 who were screened for past-year cannabis use during routine pediatric visits from 2016 to 2023 and followed through age 25 or until the end of 2023. Data analysis showed that past-year cannabis use during adolescence was associated with higher adjusted hazard ratios for incident psychiatric disorders: psychotic disorder (AHR 2.19), bipolar disorder (AHR 2.01), depressive disorders (AHR 1.34), and anxiety disorders (AHR 1.24).
Investigators conducting the research were affiliated with Kaiser Permanente, the Public Health Institute’s Getting it Right from the Start program, the University of California, San Francisco, and the University of Southern California. The study received funding from the National Institute on Drug Abuse (Grant R01DA0531920).
Electronic health record data were used to identify clinician-diagnosed psychiatric outcomes, and time-varying self-reported past-year cannabis use was obtained through universal, confidential screening in pediatric care. On average, cannabis use preceded diagnosis by 1.7 to 2.3 years, and the study’s longitudinal design supports cannabis exposure as a likely risk factor rather than an effect of pre-existing illness.
“As cannabis products grow more potent and are marketed more broadly, these findings indicate that adolescent cannabis use is linked to double the risk of incident psychotic and bipolar disorders—two of the most severe mental health conditions,” said Lynn Silver, M.D., program director of Getting it Right from the Start and a co-author of the study. She and other authors urge public health responses that reduce product potency, limit youth exposure and marketing, and treat adolescent cannabis use as a serious health concern.
Cannabis remains the most commonly used illicit substance among U.S. adolescents. National surveys show use increases across grades—from roughly 8% in 8th grade to about 26% in 12th grade—and more than 10% of teens aged 12–17 report past-year use. During the same period, average THC concentrations in cannabis flower have increased, and concentrated products reach substantially higher THC levels than historical preparations.
A notable strength of this study is its focus on any self-reported past-year use, identified through universal screening in standard pediatric care, rather than limiting analysis to heavy users or those meeting criteria for cannabis use disorder. Even after adjusting for prior psychiatric conditions and other substance use, adolescents reporting cannabis use faced substantially higher risks—particularly for psychotic and bipolar disorders.
Lead author Kelly Young-Wolff, Ph.D., senior research scientist at the Kaiser Permanente Division of Research, stated that the findings add to mounting evidence that cannabis exposure during adolescence may cause lasting harm to mental health. The authors emphasize the importance of accurate, evidence-based information for parents, young people, and clinicians to support prevention efforts.
The study also identified disparities: cannabis use was more common among adolescents enrolled in Medicaid and those living in socioeconomically deprived neighborhoods, suggesting that broader commercialization could worsen existing mental health inequities.
Key Questions Answered:
A: The study used a past-year measure, so even occasional use within the prior 12 months was associated with the increased risk reported; the elevated risk was not limited to those with heavy or daily use.
A: Because the research followed individuals over time, cannabis use most often preceded the psychiatric diagnosis by about two years, supporting a temporal relationship consistent with cannabis as a contributing risk factor rather than solely a form of self-medication.
A: One key factor is increasing THC potency. Modern cannabis products—especially concentrates and some vaped forms—can deliver much higher doses of THC than older flower preparations, which may more strongly affect an adolescent brain still undergoing development.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this cannabis use and mental health research news
Author: Renate Myles
Source: Public Health Institute
Contact: Renate Myles – Public Health Institute
Image: The image is credited to Neuroscience News
Original Research: Open access. “Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders” by Kelly C. Young-Wolff and colleagues, published in JAMA Health Forum. DOI: 10.1001/jamahealthforum.2025.6839
Abstract
Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders
Importance
As cannabis becomes more accessible and socially accepted, concerns are increasing about its effects on adolescent mental health. Prior studies have linked adolescent cannabis use to psychiatric symptoms, but large population-based longitudinal research on clinically diagnosed disorders has been limited.
Objective
To determine whether adolescent cannabis use is associated with increased risk of incident psychotic, bipolar, depressive, and anxiety disorders during adolescence and young adulthood.
Design, Setting, and Participants
This cohort study included adolescents aged 13 to 17 who were screened for past-year cannabis use at Kaiser Permanente Northern California from 2016 to 2023 and followed through age 25 or until December 31, 2023. Data were analyzed between February 21, 2024 and August 27, 2025.
Exposure
Time-varying, self-reported past-year cannabis use collected through universal, confidential screening during routine pediatric visits.
Main Outcomes and Measures
Incident clinician-diagnosed psychotic, bipolar, depressive, and anxiety disorders identified in electronic health records using International Classification of Disease codes. Cox proportional hazards models adjusted for sex, race and ethnicity, neighborhood deprivation, insurance type, and time-varying alcohol and other substance use were used to estimate associations.
Results
Among 463,396 adolescents (234,114 males, mean age 14.5 years), 26,345 (5.7%) reported past-year cannabis use at baseline. Past-year use was associated with higher risk of incident psychotic (AHR 2.19), bipolar (AHR 2.01), depressive (AHR 1.34), and anxiety disorders (AHR 1.24). Associations for depressive and anxiety disorders weakened as adolescents aged. After adjusting for prior psychiatric conditions, associations remained elevated though modestly attenuated.
Conclusions and Relevance
This cohort study found that adolescent cannabis use was associated with increased risk of incident psychiatric disorders—especially psychotic and bipolar disorders. These findings support the development of targeted clinical guidance, education for families and clinicians, and policies aimed at preventing or delaying adolescent cannabis use as legalization expands.