Young men with cannabis use disorder have an increased risk of developing schizophrenia, according to a study led by researchers at the Mental Health Services in the Capital Region of Denmark and the National Institute on Drug Abuse (NIDA) at the National Institutes of Health. The study, published in Psychological Medicine, analyzed detailed health records data over 50 years and representing more than six million people in Denmark to estimate the fraction of schizophrenia cases that could be attributed to cannabis use disorder on the population level.