New research published in the Journal of the American Medical Association associates adolescent cannabis use with increased risk for serious mental health conditions.
Scientists from Kaiser Permanente, UC San Francisco, Public Health Institute and the University of Southern California tracked nearly 500,000 teens ages 13 to 17 over an eight year period.
“(They) were confidentially screened for cannabis use as part of routine pediatric care. And then we examined the later onset of clinician-diagnosed psychotic, bipolar, depressive, and anxiety disorders within that same cohort, whereas many studies have only focused on one mental health outcome at a time,” Kelly Young-Wolff said, lead author of the study and senior research scientist at the Kaiser Permanente Division of Research.
Among all the mental health conditions examined, Young-Wolff said two stood out.
“The strongest associations were found for psychotic and bipolar disorders, where the risk was about doubled. And importantly, teens reported on their cannabis use about one to two years before their mental health diagnosis,” Young-Wolff said.
They accounted for other risk factors like sex, race ethnicity, socioeconomic disadvantage, insurance type and other substance use, she said.
“It is possible that some teens were using cannabis as a way to try to cope with early mental health symptoms, but we found that our associations remained, even after accounting for prior psychiatric conditions,” Young-Wolff said.
The study does not prove cannabis causes these disorders but the sequence, use first, diagnosis later, is concerning, Young-Wolff said.
Rady Children’s Hospital pediatrician, Dr. Natalie Laub said she’s watching similar patterns unfold in the emergency room.
“Prior to 2020, we were only seeing a handful of adolescents a year, maybe 20 or 30. In 2025, we saw nearly 600 adolescents present to the emergency room because they needed treatment of some kind for their cannabis use,” Laub, who was involved in the study, said.
Cannabis products are far more potent today than what previous generations were exposed to, Laub said.
The study also showed that teens on Medicaid and those from lower-income neighborhoods were more likely to use cannabis, highlighting concerns that wider commercialization of the drug could worsen existing mental health inequities.
“We see this public health crisis emerging in children and young adolescents with early initiation of cannabis use. They think it's cool, they think it's safe,” Laub said. “They start young, and then they develop these long-term consequences”
Laub said she worries many families underestimate the risk.
“My message to parents would be, start talking about this sooner than you think is necessary. If you're not talking about the dangers of cannabis until your child is 12, 13 or 14, it's probably too late,” she said.
More research is needed to fully understand the long-term effects of cannabis on developing brains, particularly given the growing availability and social acceptance of the drug, Young-Wolff said.
