Researchers find link between cannabis use disorder and schizophrenia

Marijuana use has increased considerably over the last decade, and its effects are causing concern among researchers.
A man smokes a joint during a 4-20 event.
Posted at 2:26 PM, May 09, 2023

A study involving the National Institute on Drug Abusefound a connection between cannabis use disorder and schizophrenia, with young men with cannabis use disorder being at the highest risk for developing schizophrenia. 

The study published earlier this month in Psychological Medicine used data from the last five decades as part of its analysis. 

According to researchers, 30% of schizophrenia cases involving men ages 21-30 could be prevented by averting cannabis use disorder. The researchers say both cannabis use disorder and schizophrenia can be treated but can "profoundly impact people’s lives."

The researchers added that those with cannabis use disorder cannot stop using cannabis despite the effects it has on their life. 

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The National Institute of Health says common symptoms of schizophrenia include hallucinations, delusions, thought disorder and movement disorder. 

"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 Dr. Nora Volkow. "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."

Data shows that marijuana use among young adults is increasing. In 2011, fewer than 30% of adults ages 19-30 said they used marijuana at some point during the year. That figure grew to over 40% by 2021. 

The percentage of daily cannabis users ages 19-30 nearly doubled, from 6% in 2011 to 11% in 2021, National Institutes of Health datashows.