A huge study finds link between cannabis use in teens and psychosis later
Summary
NPR reports on a large longitudinal study linking cannabis use in adolescence with elevated risks of bipolar and psychotic disorders later, plus increased depression and anxiety. The study analyzed ~460,000 Kaiser Permanente teens, following them to age 25 after excluding preexisting conditions, with about 4,000 cases of bipolar and psychotic disorders each. The evidence suggests a potential causal relationship but remains observational and context-dependent; implications for public health messaging and legalization debates are discussed.