Cannabis use and psychosis are sometimes associated, but the supporting evidence is not robust.
This study was designed to "evaluate the association of state medical and recreational cannabis laws and commercialization with rates of psychosis-related health care utilization." It was published by the JAMA (Journal of the American Medical Association) Network in January 2023.
The authors analyzed 2003 to 2017 Commercial and Medicare Advantage claims data for patients 16 years and older in 50 U.S. states and the District of Columbia. The data included claims for over 63 million people. Outcome measures were rates of psychosis-related diagnoses and prescribed anti-psychotic medicine. Over 7.5 million patients had psychosis-related diagnoses.
Results in the authors' words:
Results from fully-adjusted models showed that, compared with no legalization policy, states with legalization policies experienced no statistically significant increase in rates of psychosis-related diagnoses or prescribed antipsychotics
The full text article is here at JamaNetwork.com.