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• Posted February 23, 2026

Teens Using Weed Have Doubled Risk For Psychosis, Bipolar Disorder

Teens who use weed are twice as likely to develop psychotic or bipolar disorders, a new study says.

They also are more likely to have depression and anxiety, researchers reported Feb. 20 in JAMA Health Forum.

“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,” researcher Dr. Lynn Silver said in a news release. She’s a program director at the Public Health Institute in Oakland, California.

More than 10% of 12- to 17-year-olds in the U.S. have used weed within the past year, researchers said in background notes. By their senior year in high school, about 26% of U.S. teenagers have tried it.

These teens are using cannabis that packs a more powerful punch. Today’s weed has THC levels that exceed 20%, far higher than in previous decades.

“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,” Silver said.

For the study, researchers analyzed health records of more than 463,000 teens aged 13 to 17 who were screened for past-year weed use at Kaiser Permanente Northern California between 2016 and 2023.

The research team tracked the teens through age 26 to see how prior weed use might affect their risk for mental health disorders.

Results showed that weed use was associated with a doubled risk of psychotic and bipolar disorders; a 34% increased risk of depression; and a 24% increased risk of anxiety.

Risk for these mental health problems remained about as high even after researchers adjusted for past psychiatric conditions among the teenagers, the study noted.

On average, weed use preceded mental health diagnoses by an average of 1.7 to 2.3 years, researchers found.

“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,” lead researcher Kelly Young-Wolff, a senior research scientist at the Kaiser Permanente Division of Research, said in a news release.

“This study adds to the growing body of evidence that cannabis use during adolescence could have potentially detrimental, long-term health effects,” Young-Wolff said. “It’s imperative that parents and their children have accurate, trusted and evidence-based information about the risks of adolescent cannabis use.”

 More information

The U.S. Centers for Disease Control and Prevention has more on cannabis and teens.

SOURCES: Public Health Institute, news release, Feb. 20, 2026; JAMA Health Forum, Feb. 20, 2026