Adolescent cannabis use is linked to a significantly increased risk of developing serious psychiatric disorders in young adulthood, according to a large new study published February 20, 2026, in JAMA Health Forum. Understanding the potential mental health consequences of cannabis use during adolescence is crucial for public health initiatives.
The study, which tracked 463,396 adolescents aged 13 to 17 through age 26, found that those who reported cannabis use in the past year of adolescence had doubled the risk of developing psychotic and bipolar disorders. It also showed a “significant” increase in the likelihood of experiencing depression or anxiety.
Researchers from Kaiser Permanente, the Public Health Institute, the University of California, San Francisco, and the University of Southern California analyzed data from electronic health records of routine pediatric visits between 2016 and 2023 to conduct the research.
On average, adolescents who had used cannabis were diagnosed with a psychiatric disorder 1.7 to 2.3 years later.
The study’s longitudinal design strengthens the evidence that exposure to cannabis during adolescence is a potential risk factor for the development of mental illness, the authors note.
“As cannabis becomes more potent and is marketed more aggressively, this study shows that adolescent use is associated with a doubled risk of psychotic and bipolar disorders – two of the most serious mental health conditions,” said Lynn Silver, director of the Getting it Right from the Start program at the Public Health Institute and a study co-author.
Cannabis is the most commonly used illicit drug among U.S. Teenagers. According to the ‘Monitoring the Future’ study, use increases with grade level (from 8% in 8th grade, or ages 13-14, to 26% in 12th grade, or ages 17-18).
More than 10% of adolescents aged 12 to 17 reported using cannabis in the past year, according to the 2024 National Survey on Drug Use, and Health.
Adding to concerns, the average THC levels in cannabis flower in California now exceed 20%, much higher than in previous decades, and concentrates can surpass 95% THC.
Unlike other research, this study examined any reported cannabis use in the past year through universal screening of adolescents during standard pediatric care, rather than focusing solely on heavy use or cannabis use disorder.
“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,” cautioned lead study author Kelly Young-Wolff.
“It is imperative that parents and their children have accurate, evidence-based information about the risks,” she added.
The study also found that cannabis use was more common among adolescents enrolled in Medicaid and those living in neighborhoods with greater socioeconomic disadvantage, suggesting the drug could exacerbate existing mental health disparities.
