Teenagers who use cannabis face a significantly higher risk of developing psychiatric disorders, particularly bipolar and psychotic conditions. A large-scale study tracked nearly half a million adolescents over seven years to examine these effects.
Persistent risks into young adulthood
The research, published in JAMA Health Forum, followed 460,000 teens aged 13 to 17 within Kaiser Permanente Northern California from 2016 to 2023. About 5.7% reported cannabis use in the previous year—an average of 1.7 to 2.3 years before receiving a psychiatric diagnosis.
Those participants were more than twice as likely to later develop a psychotic disorder and about twice as likely to be diagnosed with bipolar disorder. Depression and anxiety risks increased by 34% and 24%, though the rise was less pronounced.
The connection remained strong even after accounting for prior mental health conditions, alcohol use, and socioeconomic status. Psychotic and bipolar disorder risks continued into young adulthood, while the link to depression and anxiety faded as participants aged.
A vulnerable period for the developing brain
Kelly C. Young-Wolff, the study’s lead researcher and a senior scientist at Kaiser Permanente, noted that adolescence may be a particularly sensitive time for cannabis-related harm. “Adolescents who report cannabis use have a significantly higher risk of developing multiple psychiatric disorders,” she said.
The investigation adjusted for sex, race, ethnicity, and neighborhood socioeconomic status. This approach made the results more representative of today’s diverse adolescent population than many earlier studies. Unlike past research, which often focused on heavy users, this analysis included any self-reported cannabis use in the previous year.
One challenge is that some teens may use cannabis to ease early mental health symptoms before receiving a diagnosis. The study’s design—tracking participants from adolescence into young adulthood—helped clarify timing, though it couldn’t prove causation.
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Today’s cannabis products contain much higher THC concentrations than those available decades ago. High-potency cannabis may interfere with the brain’s cannabinoid system, which regulates emotion, motivation, and thinking.
This study isn’t the first to highlight concerns about adolescent cannabis use, but it strengthens the case that legalization and social acceptance haven’t eliminated risks. Earlier work often relied on smaller, less diverse groups or extreme cases, leaving gaps in understanding how even occasional use might affect long-term mental health.
Guidance for parents and providers
The authors emphasize that the findings should guide discussions rather than cause alarm. With cannabis now legal in many states, families and healthcare providers can address its potential risks—especially during adolescence, when the brain is still maturing.
“These results add to growing evidence that adolescence may be a particularly vulnerable time for cannabis-related harms,” Young-Wolff said. The data came from confidential questionnaires completed before routine medical visits, offering a realistic view of teen behavior.
While the study doesn’t prove cannabis directly causes psychiatric disorders, it highlights the importance of informed conversations about its use during a critical stage of brain development. Tools like healthy lifestyle resources can help teens make better choices.
Sleep also plays a key role in mental health. Prioritizing rest may reduce some risks associated with adolescent stress and substance use.
