New Research Fails to Show a Correlation Between Marijuana, Suicide, and Mental Illness

Some critics of marijuana legalization point to studies suggesting that regular use might increase the risk of mental illness or suicide. In 2013, research by Anderson, et al found no such relationship in states that had legalized medicinal marijuana. My colleagues Jacob J. Rich, Michael Schemenaur, and Robert Capodilupo and I did research to see if Anderson’s findings are still valid in 2021. As of 2021, 19 states and the District of Columbia have legalized marijuana for recreational use and medicinal marijuana is available in 35 states. We performed a state‐​level longitudinal analysis using suicide rates from the National Center for Health Statistics and mental health morbidity rates from the National Survey on Drug Use and Health following the procedures outlined by Anderson et al.We found that recreational marijuana access was associated with a 6.29 percent reduction in suicide rates for males aged 40 to 49, but no other mental health outcomes were otherwise affected by liberalization of marijuana laws.The pre‐​print of our study is now available for viewing at medRxiv. It is currently awaiting peer review for publication in a major scientific journal. The pdf of the study that includes the graphics along with the text can be found here.(Rich and Schemenaur were both Cato Research Assistants in health policy when we began our study and are now working towards their PhDs at Case Western Reserve University and the University of Arizona respectively. Jacob Rich is also a policy analyst at Reason Foundation. Capodilupo was a Cato intern at the time. He is now attending law school at Yale University.)