Early Cannabis Use in Teens Linked to Double Risk of Psychotic and Bipolar Disorders

A large, population-based study of 463,396 adolescents followed from ages 13–17 into young adulthood found that past-year cannabis use was associated with about double the risk of incident psychotic and bipolar disorders, with diagnoses typically emerging 1.7–2.3 years after first use. The findings held after adjusting for prior mental health and other substances, and researchers note rising cannabis potency (flower >20% THC, concentrates up to 95%) may drive the risk, underscoring the need for prevention and policy measures.