Rationale: Cannabis use has been linked to psychosis and schizophrenia in some people. Higher-potency cannabis products are linked to higher rates of schizophrenia.

Method: Researchers examined changes in schizophrenia prevalence associated with CUD between 2006 and 2022. Data from over 13 million people in Ontario, Canada was collected from national health datasets. Analyses were performed separately for males and females amongst four different age groups: 14 to 18 years, 19 to 24 years, 25 to 44 years, and 45 to 65 years.

Results: 0.9% of individuals during the study period had a hospital visit for cannabis use disorder; these individuals were 15x more likely to develop schizophrenia. If severe cannabis use that requires hospitalization were eliminated, the proportion of schizophrenia cases that could have been prevented increased from 1.6% in 2006 to 9.6% in 2022.

Meaning: These findings suggest that cannabis legalization is associated with increased risk of developing psychosis/schizophrenia.