Increasing evidence points to a strong link between having a marijuana use disorder (addiction) and developing schizophrenia, particularly for young males. New research published in Psychological Medicine investigated this linkage on a population level by examining 50 years of health data on over 6.9 million people in Denmark. The researchers found that from 1972 to 2021, schizophrenia cases likely attributed to marijuana use disorder have steadily increased for both males and females. They estimated that the number of schizophrenia cases in 2021 (15% in males and 4% in females) could have been drastically prevented if not for the individuals marijuana use disorder. When analyzed by age and gender, they found a drastic rise in the number of schizophrenia cases attributed to marijuana use disorder for young males ages 16 to 25. Notably, they estimate that 30% of schizophrenia cases in young males could have been prevented if they did not have a marijuana use disorder.

These findings are associated with changing marijuana laws and the drastic rise in strength of marijuana products which have led to an increase in marijuana use, frequency of use, and diagnoses of marijuana use disorder. Both marijuana use disorder and schizophrenia are severe mental health conditions that greatly impact those diagnosed and the effects are far reaching. It is critical to acknowledge and educate about the growing body of literature emphasizing the detrimental impact legalizing and commercializing marijuana has on a population level. Marijuana is not harmless and its use can have severe outcomes on one’s mental health and society.


  • Hjorthøj, C., Compton, W., Starzer, M., Nordholm, D., Einstein, E., Erlangsen, A., Nordentoft, M., Volkow, N. D., & Han, B. (2023). Association between cannabis use disorder and schizophrenia stronger in young males than in females. Psychological Medicine. doi:10.1017/S0033291723000880
  • National Institute on Drug Abuse. (May 4, 2023). Young men at highest risk of schizophrenia linked with cannabis use disorder.