Psychosis-Related Outcomes Not Linked To State Cannabis Legalization, Finds Study Of 64M Americans

A recent study done by a team of Stanford University researchers concluded that there is no statistically significant difference in the rates of psychosis-related diagnoses and prescribed antipsychotics in states with medical or recreational cannabis policies as compared with states with no such policies.

“As states continue to introduce cannabis legislation, a thorough and comprehensive understanding of their potential health outcomes is essential,” said the study authors.

“This study is the first and largest, to our knowledge, to quantify the association of medical and recreational cannabis policies with rates of psychosis-related health care claims across US states.” The study was published in JAMA Network Open.

Findings: In this cohort study of claims data from nearly 64 million commercial insurance and Medicare beneficiaries from 2003 to 2017, there was no statistically significant difference in the rates of psychosis-related diagnoses or prescribed antipsychotics in states with medical or recreational cannabis policies compared to states without.

The authors concluded that the study’s findings do not support an association between state policies legalizing cannabis and psychosis-related outcomes though add that “further research into this topic may be informative.”

Why is this important? Psychosis has been a hypothesized consequence of cannabis use. Legalization of cannabis could therefore be associated with an increase in rates of health care utilization for psychosis.

“Psychotic disorders are known to cause considerable personal hardship and may impede an individual’s ability to complete their education, maintain employment, and otherwise function as expected in society,” the authors say.

As US states continue to legalize the use, production, promotion, or sale of cannabis, continued examination of the implications of state cannabis policies for psychotic disorders can be not only informative but important, particularly for high-risk population subgroups, the authors conclude.

The Stanford study comes shortly after a separate investigation published online in the journal Psychological Medicine, which found no increased rates of psychosis among twins who live in legal cannabis states as compared to their siblings who did not.