A recent study published in JAMA Health Forum reports that adolescents who use cannabis face a higher risk of developing psychiatric disorders by young adulthood. The research followed 463,396 individuals aged 13 to 17 through age 26 and found that past-year cannabis use during adolescence was linked to an increased likelihood of developing psychotic and bipolar disorders—both risks were doubled—as well as depressive and anxiety disorders.
The study was conducted by 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. It received funding from the National Institute on Drug Abuse.
Researchers analyzed electronic health record data collected from routine pediatric visits between 2016 and 2023. They observed that cannabis use typically occurred about one to two years before any psychiatric diagnosis. This longitudinal approach provides evidence that exposure to cannabis in adolescence may be a risk factor for later mental illness.
Cannabis remains the most commonly used illicit drug among U.S. adolescents. Data show usage rates increase with age: approximately 8% of eighth graders report using cannabis, compared to about 26% of twelfth graders. According to the latest National Survey on Drug Use and Health, over 10% of teens aged 12 to 17 reported using cannabis in the past year. In addition, THC concentrations in California’s cannabis products have risen significantly in recent years.
Unlike earlier studies focusing mainly on heavy users or those with diagnosed cannabis use disorder, this research included any self-reported past-year use based on universal screening during pediatric care.
"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," said Kelly Young-Wolff, Ph.D., lead author of the study and senior research scientist at the Kaiser Permanente Division of Research. "This study adds to the growing body of evidence that cannabis use during adolescence could have potentially detrimental, long-term health effects. It's imperative that parents and their children have accurate, trusted, and evidence-based information about the risks of adolescent cannabis use."
The findings also indicate that adolescent cannabis use is more prevalent among those enrolled in Medicaid or living in socioeconomically deprived neighborhoods. Researchers caution that increased commercialization of cannabis could worsen existing mental health disparities.
