Young men at highest risk of schizophrenia linked with cannabis use disorder

Thursday, May 4, 2023

NIH study highlights the need to proactively screen for, prevent, and treat cannabis use disorder especially among young people

Young men with cannabis (marijuana) 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 spanning five decades 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.

Researchers found strong evidence of an association between cannabis use disorder and schizophrenia among men and women, though the association was much stronger among young men. Using statistical models, the study authors estimated that as many as 30 percent of cases of schizophrenia among men aged 21-30 might have been prevented by averting cannabis use disorder.

Cannabis use disorder and schizophrenia are serious, but treatable, mental disorders that can profoundly impact people’s lives. People with cannabis use disorder are unable to stop using cannabis despite it causing negative consequences in their lives. Schizophrenia is a serious mental illness that affects how a person thinks, feels, and behaves. People with schizophrenia may seem like they have lost touch with reality, and the symptoms of schizophrenia can make it difficult to participate in usual, everyday activities. However, effective treatments are available for both cannabis use disorder and schizophrenia.

“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,” said NIDA Director and study coauthor Nora Volkow, M.D. “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 one 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.”