Adolescent Cannabis Use Tied to Increased Risk of Severe Mental Disorders by Age 26

A comprehensive longitudinal study tracking 463,396 adolescents aged 13 to 17 through age 26 has identified a significant association between cannabis use during teenage years and elevated risks of serious psychiatric disorders.

Published in JAMA Health Forum on February 20, 2026, the research found that cannabis use within the past year during adolescence corresponded with doubled risks of newly diagnosed psychotic and bipolar disorders, as well as increased incidences of depressive and anxiety disorders.

The investigation was conducted by researchers 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. Funding was provided by the National Institute on Drug Abuse through grant R01DA0531920.

Utilizing electronic health records from routine pediatric visits between 2016 and 2023, the study observed that cannabis use was documented on average 1.7 to 2.3 years prior to the onset of psychiatric diagnoses. This longitudinal design strengthens the evidence suggesting adolescent cannabis exposure may be a risk factor for subsequent mental illness.

Lynn Silver, M.D., program director of the Getting it Right from the Start initiative and co-author of the study, stated, “As cannabis becomes more potent and aggressively marketed, this study indicates that adolescent cannabis use is associated with double the risk of incident psychotic and bipolar disorders, two of the most serious mental health conditions.” She emphasized the necessity for urgent public health measures aimed at reducing product potency, preventing youth exposure and marketing, and treating adolescent cannabis use as a significant health concern.

Cannabis remains the most frequently used illicit substance among U.S. adolescents. Data from the Monitoring the Future study show usage rates increasing from approximately 8% in eighth grade to 26% in twelfth grade. The 2024 National Survey on Drug Use and Health reported that over 10% of U.S. teens aged 12 to 17 used cannabis in the past year. Concurrently, average THC concentrations in California cannabis flower exceed 20%, with concentrates containing over 95% THC, markedly higher than in previous decades.

This research expanded on prior studies by including any self-reported cannabis use within the past year, based on universal screening during routine pediatric care, rather than focusing solely on heavy use or cannabis use disorder.

Kelly Young-Wolff, Ph.D., lead author and senior research scientist at Kaiser Permanente Division of Research, noted, “Even after accounting for prior mental health conditions and other substance use, adolescents who reported cannabis use had a substantially higher risk of developing psychiatric disorders—particularly psychotic and bipolar disorders.” She highlighted the importance of providing parents and youth with accurate, evidence-based information regarding the risks associated with adolescent cannabis use.

The study also identified higher rates of cannabis use among adolescents enrolled in Medicaid and those residing in socioeconomically disadvantaged neighborhoods, suggesting that increased cannabis commercialization may exacerbate existing mental health disparities.

The full study, titled “Adolescent Cannabis Use and Risk of Psychotic, Bipolar, Depressive, and Anxiety Disorders,” was authored by Kelly C. Young-Wolff and colleagues and published on February 20, 2026, in JAMA Health Forum. The DOI is 10.1001/jamahealthforum.2025.6839.

This research was supported by grant R01 DA0531920 from the NIH/NIDA.