Heavy Marijuana Use Increases Schizophrenia in Men, Study Finds

Young men who use potent marijuana frequently have an increased risk of developing schizophrenia, according to a new study of almost 7 million health records.

As many as 30% of cases of schizophrenia among men aged 21-to-30 could have been prevented had they avoided cannabis use disorder, according to the study published Thursday in Psychological Medicine. The condition, loosely defined as frequent use of the drug despite negative consequences, has been found to develop in around three in 10 who use marijuana, according to past research. The latest study, based on Danish health records, adds to growing research into cannabis and mental health outcomes in the US and other countries.