A large 2026 cohort study found that adolescents reporting cannabis use were more likely to later receive diagnoses of psychotic, bipolar, depressive, and anxiety disorders. This Evidence Watch review explains what the paper actually shows, where the associations are strongest, and why the findings deserve clinical attention. It also makes clear what the study does not prove, especially around causality, product type, and individual risk.
Adolescent Cannabis Use Linked to Doubling Risk of Psychotic and Bipolar Disorders
Nearly half a million teens were tracked in this study, and the data shows cannabis use during adolescence meaningfully increases the chance of serious psychiatric diagnoses in early adulthood. A large longitudinal cohort study published in JAMA Health Forum tracked 463,396 adolescents and found that cannabis use between ages 13 and 17 was associated with approximately double the risk of psychotic and bipolar disorders by age 26. Elevated risks for depression and anxiety were also observed.