Young men with cannabis use disorder are at an increased risk of developing schizophrenia...
...according to a study released this week by the National Institute on Drug Abuse (NIDA) at the National Institutes of Health (NIH).
Findings from the study, which was led by researchers at the Mental Health Services in the Capital Region of Denmark and NIDA, were published in the journal Psychological Medicine.
Aiming to estimate the number of schizophrenia cases that could be attributed to cannabis use disorder, researchers looked at health records data of 6.9 million people in Denmark who were between the ages of 16 and 49 at some point between 1972 and 2021.
Strong evidence of an association between cannabis use disorder and schizophrenia was observed among both men and women, although the association was significantly stronger among men. The researchers estimate that as many as 30% of schizophrenia cases among men between the ages of 21 and 30 could have been prevented by avoiding cannabis use disorder. For men between the ages of 16 and 49, the rate of preventable cases of schizophrenia was 15%, compared to 4% of women’s cases in the same age range.
“The entanglement of substance use disorders and mental illnesses is a major public health issue, requiring urgent action and support for people who need it,” NIDA Director and study coauthor Nora Volkow, MD, said in a news release. “As access to potent cannabis products continues to expand, it is crucial that we also expand prevention, screening, and treatment for people who may experience mental illnesses associated with cannabis use.
“The findings from this study are 1 step in that direction and can help inform decisions that health care providers may make in caring for patients, as well as decisions that individuals may make about their own cannabis use.”
The study authors added that their research backs previous findings that suggest the proportion of new schizophrenia cases that are potentially attributable to cannabis use disorder has increased over the past 5 decades, likely because of higher potency cannabis and increasing prevalence of cannabis use disorder diagnoses.
The authors added that additional research is needed to explore potential differences in potency and frequency of cannabis consumption between young men and women, and to examine the mechanisms underlying young men’s increased vulnerability to the effects of cannabis on schizophrenia.