Rate of increase low for psychosis-related outcomes in states with cannabis laws
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States that enacted medical and recreational policies on cannabis did not see significant increases in rates of psychosis-related health outcomes compared with those that did not, per a study published in JAMA Network Open.
“Psychosis has long been investigated as a potential consequence of cannabis use,” Holly Elser, MD, PhD, of the department of neurology at the Hospital of the University of Pennsylvania. ”Whether cannabis plays a causal role in the onset of psychosis nevertheless remains a point of controversy.”
Elser and colleagues aimed to evaluate associations between medical and recreational cannabis commercialization and laws by state, along with rates of health care utilization as a result of psychosis.
Their retrospective cohort study examined commercial and Medicare Advantage claims data between 2003 and 2017, to identify more than 63 million beneficiaries at least 16 years of age, from all 50 states and the District of Columbia. Main outcomes for the study were rates of psychosis-related diagnoses and amount of antipsychotic medication prescribed. Policies for each state’s cannabis legalization were measured per month based on medical or recreational law, as well as the presence or absence of retail sales.
The researchers logged more than 7.5 million psychosis-related diagnoses and 20.8 million filled prescriptions across the study period and found 29 stated ratified legalization policies for either recreational or medical cannabis.
Fully adjusted models showed that, compared with states that did not legalize, states with legalization policies experienced no statistically significant increase in rates of psychosis-related diagnoses (medical, no retail outlets: RR, 1.13; 95% CI, 0.97-1.36; medical, retail outlets: RR, 1.24; 95% CI, 0.96-1.61; recreational, no retail outlets: RR, 1.38; 95% CI, 0.93-2.04; recreational, retail outlets: RR, 1.39; 95% CI, 0.98-1.97) or prescribed antipsychotics (medical, no retail outlets: RR, 1.00; 95% CI, 0.88-1.13; medical, retail outlets: RR, 1.01; 95% CI, 0.87-1.19; recreational, no retail outlets: RR, 1.13; 95% CI, 0.84-1.51; recreational, retail outlets: RR, 1.14; 95% CI, 0.89-1.45).
However, data showed that rates of psychosis-related diagnoses increased significantly among men, individuals aged 55 to 64 years and Asian individuals in states that enacted recreational cannabis policies compared with those that did not.
“As U.S. states continue to legalize the use, production, promotion or sale of cannabis, continued examination of the implications of state cannabis policies for psychotic disorders may be informative,” Elser and colleagues wrote. “Particularly with study designs that yield precise estimates in high-risk population subgroups.”