Substance Use
Recreational cannabis legalization and serious mental disorder among cannabis patients in California: A statewide longitudinal study Sidra Goldman-Mellor* Sidra Goldman-Mellor Goldman-Mellor Goldman-Mellor University of California, Merced
More than 50% of U.S. residents live in states with legalized recreational use of cannabis. Cannabis use is associated with adverse mental health outcomes, and research suggests that recreational cannabis legalization (RCL) has led to population-level increases in incidence of serious mental disorder. No studies, however, have examined whether RCL is associated with changes in such risk among individuals with problematic cannabis use (the most vulnerable group). Using statewide linked emergency department (ED) data from California, we examined 12-month risk of serious mental disorder ED visits among >500,000 cannabis ED patients presenting before vs. after RCL in CA (2011-2016 vs. 2017-2021), comparing such risk to that of (a) alcohol ED patients and (b) a random sample of other ED patients. Patients were matched on sociodemographic characteristics and comorbid mental health and substance use. Using risk ratio models with interaction terms, we found that risk of mental disorder ED visits was equivalent among cannabis and alcohol patients prior to RCL, but that cannabis patients’ risk significantly decreased after RCL while alcohol patients’ risk remained stable (interaction term RR=0.91, p<0.001). Compared to the ED random-sample patients, cannabis patients had elevated mental disorder risk prior to RCL; both patient groups’ risk declined after RCL, but the decrease was greater among the random-sample patients (interaction term RR=1.03, p<0.001). These overall patterns were largely due to shifts in incidence of ED visits specifically for major depression, anxiety, and suicidal behavior. In summary, cannabis ED patients exhibited a decrease in mental disorder risk after RCL, but our findings may reflect population-wide shifts in mental disorder vulnerability rather than a distinct effect of RCL. More research is needed to understand longer-term patterns and potential subgroup-specific effects in the association between RCL and mental disorder among cannabis patients.
