A huge study finds a link between cannabis use in teens and psychosis later

February 21, 2026 - 19:04

A landmark study tracking hundreds of thousands of individuals from adolescence into adulthood has delivered compelling new evidence on the mental health risks of early cannabis use. The research, one of the largest of its kind, followed more than 400,000 teenagers over several years.

The findings indicate a clear association: teenagers who used marijuana were significantly more likely to develop serious mental illness later in life compared to their peers who did not. The study specifically highlights an increased risk for psychotic disorders, which can involve a loss of contact with reality. Beyond psychosis, the data also points to heightened risks for clinical depression and anxiety disorders in adulthood.

This extensive research adds substantial weight to growing concerns among public health experts regarding the impact of cannabis on the developing adolescent brain. The study's scale and longitudinal design strengthen the argument that early exposure may act as a catalyst or contributing factor for certain mental health conditions, underscoring the importance of targeted education and prevention efforts aimed at youth.