Study published in JAMA Health Forum on Feb. 20, 2026, reports that teens who use cannabis may have a substantially greater chance of developing serious psychiatric conditions by young adulthood.
The longitudinal study followed 463,396 adolescents ages 13 to 17 through age 26 and found that cannabis use in the past year during adolescence was associated with significantly higher risks of newly diagnosed psychotic disorders, which doubled; bipolar disorders, which doubled; depressive disorders; and anxiety disorders.
Researchers from Kaiser Permanente, the Public Health Institute’s Getting it Right from the Start, the University of California, San Francisco and the University of Southern California conducted the study, which was funded by a grant from NIH’s National Institute on Drug Abuse (R01DA0531920).
Records tracked risk over time
The research used electronic health record data from routine pediatric visits conducted from 2016 through 2023. On average, cannabis use was recorded 1.7 to 2.3 years before a psychiatric diagnosis appeared. Because the study followed adolescents over time, its design adds stronger evidence that cannabis exposure during the teen years may be a risk factor for later mental illness.
“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,” said Lynn Silver, M.D., program director of the Getting it Right from the Start, a program of the Public Health Institute, and a study co-author. “The evidence increasingly points to the need for an urgent public health response — one that reduces product potency, prioritizes prevention, limits youth exposure and marketing and treats adolescent cannabis use as a serious health issue, not a benign behavior.”
Cannabis is the most commonly used illicit drug among adolescents in the United States. The Monitoring the Future study shows that use increases as students get older, rising from about 8% in 8th grade to 26% in 12th grade. The 2024 National Survey on Drug Use and Health also found that more than 10% of U.S. teens ages 12 to 17 reported cannabis use in the past year. At the same time, average THC levels in California cannabis flower now exceed 20%, far above levels seen in earlier decades, while cannabis concentrates can contain more than 95% THC.
