Among over 100,000 Kaiser Permanente adolescents screened for cannabis use, those who reported using had significantly higher rates of psychotic, bipolar, depressive, and anxiety disorders diagnosed by clinicians through age 25.
Pediatricians screening adolescents, parents of teenagers who use cannabis, mental health clinicians, adolescent health policymakers.
What the researchers found
This large longitudinal cohort study followed adolescents aged 13–17 who were screened for past-year cannabis use during routine pediatric care at Kaiser Permanente Northern California from 2016 to 2023, with follow-up through age 25.
Adolescents who reported cannabis use had significantly higher rates of clinician-diagnosed psychiatric disorders compared to non-users. The associations held across all four disorder categories examined: psychotic disorders, bipolar disorder, depressive disorders, and anxiety disorders.
The strength of this study lies in its design: cannabis use was captured through universal, confidential screening during standard medical visits (reducing selection bias), and psychiatric outcomes were clinician-diagnosed conditions recorded in electronic health records (more reliable than self-reported symptoms). Cox proportional hazards regression accounted for time-varying cannabis exposure, allowing the analysis to capture changes in use status over the follow-up period.
The population-based setting and large sample size provided statistical power to examine disorders that are relatively uncommon in adolescence (particularly psychotic and bipolar disorders).
Why it matters
Published in JAMA Health Forum, this is one of the largest and most methodologically rigorous studies linking adolescent cannabis use to clinician-diagnosed psychiatric disorders. The universal screening design captures a more representative population than studies relying on treatment-seeking or survey samples, and the electronic health record outcomes are more reliable than self-reported symptoms.
The numbers in context
Adolescents ages 13–17 screened 2016–2023 at Kaiser Permanente Northern California. Followed through age 25. Four outcome categories: psychotic disorders, bipolar disorder, depressive disorders, anxiety disorders. All four significantly elevated in cannabis users vs. non-users. Time-varying cannabis use modeled in Cox regression.
How the study worked
Longitudinal cohort study of adolescents ages 13–17 screened at Kaiser Permanente Northern California, 2016–2023, with follow-up through age 25 or December 31, 2023. Time-varying self-reported past-year cannabis use from universal confidential screening. Outcomes: clinician-diagnosed psychotic, bipolar, depressive, and anxiety disorders from electronic health records. Cox proportional hazards regression models.
Who was studied
N=463,396 adolescents aged 13-17, 50.5% male, California.
What this study cannot tell us
Observational study — cannot prove cannabis caused the psychiatric disorders. Adolescents who use cannabis may differ from non-users in unmeasured ways (genetics, trauma history, family psychiatric history) that independently increase psychiatric risk. Cannabis use was self-reported during screening, though the confidential clinical setting may improve accuracy. Kaiser members may not represent all adolescents.
How to read the evidence
Large population-based longitudinal cohort with clinician-diagnosed outcomes from electronic health records — one of the strongest observational designs available, published in a JAMA journal.
When this study was published
Published in 2026 with data through 2023, providing the most current large-scale longitudinal evidence on adolescent cannabis use and psychiatric outcomes.
The bigger picture
This study provides the population-level epidemiological anchor for the psychiatric risk evidence scattered across this database. The psychosis meta-analysis (RTHC-00251) found ~34% of cannabis-induced psychosis cases convert to schizophrenia. The placental gene study (RTHC-00254) found molecular mechanisms linking prenatal THC to schizophrenia. The antipsychotic dosing study (RTHC-00261) addressed treatment after cannabis psychosis. This Kaiser study provides the foundational longitudinal data showing that adolescent cannabis use precedes clinically diagnosed psychiatric disorders at elevated rates across the full spectrum of major mental illness.
Replication
Not stated in abstract.
Funding
Not reported in abstract.
Conflicts of interest
Not reported in abstract.
Questions still open
- Is there a threshold of cannabis use frequency or duration below which psychiatric risk is not elevated? Do the associations differ by cannabis potency or product type? Would universal adolescent cannabis screening with targeted intervention reduce the incidence of psychiatric disorders?
Read the original research
Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders.
JAMA health forum, 7(2), e256839
JAMA Health Forum is a reputable journal focusing on health policy and clinical research.
Citation
Young-Wolff, Kelly C; Cortez, Catherine A; Alexeeff, Stacey E; Silver, Lynn D; Pacula, Rosalie Liccardo; Slama, Natalie E; Padon, Alisa A; Satre, Derek D; Campbell, Cynthia I; Koshy, Maria T; Does, Monique B; Sterling, Stacy A. (2026). Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders.. JAMA health forum, 7(2), e256839. https://doi.org/10.1001/jamahealthforum.2025.6839
Explore the wider topic
- How THC Affects Your Amygdala: The Brain's Threat Detector and Cannabis
- The Anandamide Connection: Your Body's Natural Bliss Molecule
- How Long for Cannabinoid Receptors to Return to Normal
- Cannabis and the Developing Brain: What Every Teenager (and Parent) Should Know
- Why Can't I Enjoy Anything Without Weed? The Science Behind It
- Dopamine Recovery After Quitting Weed: What the Science Says
- The Endocannabinoid System Explained Simply: What It Does and Why It Matters
- Your Endocannabinoid System Explained: Why Withdrawal Happens
- Your Nervous System After Quitting Weed: Fight or Flight
- Using Weed Under 18: What It Does to Your Developing Brain
- What THC Does to Your Brain: Why Withdrawal Happens
- THC and Your Prefrontal Cortex: What Cannabis Does to Your Decision-Making Brain
- Weed, Cortisol, and Stress: What Cannabis Does to Your Stress Hormones
- Weed and Memory: What the Science Says About THC and Your Hippocampus
- Weed and Motivation: Is Amotivational Syndrome Real?
- Weed and Your Nervous System: What THC Actually Does to Your Brain and Body
- How Weed Rewires Your Reward System (And How to Reset It)
- Why Does Weed Make Me Anxious Now When It Didn't Before