February 9, 2023

A recent cohort study found no increase in psychosis-related diagnoses or prescribed antipsychotics in states that have legalized cannabis for medical or adult-use compared to those that continue to uphold cannabis prohibition. The researchers from Stanford University and the University of Pennsylvania who conducted the study, utilized data of more than 63 million healthcare beneficiaries from 2003-2017 to compare rates of psychosis-related diagnoses and prescribed anti-psychotics between states.

The authors of the study did a secondary evaluation and found a small increase in men, persons aged 55-64, and Asian subgroups. Though the authors acknowledged that they did not adjust for multiple comparisons when conducting the secondary analyses which can lead to a false-positive result in the association.

While legalizing cannabis is often purported to likely lead to dire health outcomes, this premise is founded on very limited evidence as further demonstrated by these study results. It also underscores the importance of additional research moving forward on cannabis’ efficacy as a treatment for psychological conditions and the impact of cannabis on subgroups that are sensitive or prone to cannabis.