According to a study published in the Journal of the American Medical Association Network Open has found that “states with legalization policies experienced no statistically significant increase in rates of psychosis-related diagnoses”.
As noted by the study’s authors, psychosis is a hypothesized consequence of cannabis use. Legalizing cannabis “could therefore be associated with an increase in rates of health care utilization for psychosis.”
The objective of this study, which was conducted by researchers at Stanford University, the University of Pennsylvania, New York University and the Veterans Affairs Palo Alto Health Care System evaluated “the association of state medical and recreational cannabis laws and commercialization with rates of psychosis-related health care utilization.”
For the study, researchers used a retrospective cohort design using state-level panel fixed effects to model within-state changes in monthly rates of psychosis-related health care claims as a function of state cannabis policy level, adjusting for time-varying state-level characteristics and state, year, and month fixed effects. Commercial and Medicare Advantage claims data for beneficiaries aged 16 years and older in all 50 US states and the District of Columbia, 2003 to 2017 were used. Data were analyzed from April 2021 to October 2022. Outcomes were rates of psychosis-related diagnoses and prescribed antipsychotics.
This study included 63,680,589 beneficiaries. Women accounted for 51.8% of follow-up time with the majority of person-months recorded for those aged 65 years and older (77.3%) and among White beneficiaries (64.6%). 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.”
Researchers conclude by stating that “In this retrospective cohort study of commercial and Medicare Advantage claims data, state medical and recreational cannabis policies were not associated with a statistically significant increase in rates of psychosis-related health outcomes. As states continue to introduce new cannabis policies, continued evaluation of psychosis as a potential consequence of state cannabis legalization may be informative.”
For the study’s full abstract and text, click here.