Analysis: Incidences of Acute Cannabis-Induced Psychosis Are Uncommon

LAUSANNE, SWITZERLAND: According to research published in the journal Translational Psychiatry, acute psychotic episodes are only sporadically brought on by cannabis use in patients who do not already have a psychiatric disorder.

A multidisciplinary group of researchers from Australia, Switzerland, and the United Kingdom assessed the lifetime occurrences of “cannabis-associated psychotic symptoms” (CAPS) requiring hospitalization in a cohort of 233,000 European cannabis users.

According to the authors, fewer than 0.5% of people claimed to have ever had such an interaction. Such incidents were more likely to occur in younger responders and those who had a history of bipolar, anxiety, depressive, or psychotic disorder.

“Our results are consistent with the idea of a single (genetic) vulnerability signalling risk that is common across mental illnesses,” the authors wrote in their conclusion. The researchers concluded that “rates of CAPS as found here are comparable to rates of other drug-induced psychosis, such as alcohol-associated psychosis (about 0.4-0.7 percent)”.

The findings of this study are consistent with those of another study, which discovered that patients who use medical cannabis have a “low” chance of experiencing psychiatric hospitalizations as a result of their cannabis use. The journal Substance Use & Misuse published the results of that study in July. In order to assess cannabis-related hospitalizations, researchers in that study examined a cohort of over 23,000 patients over a median length of 240 days. For “mental or behavioral difficulties related to the use of cannabis,” only 26 patients were hospitalized at that time.

The results disprove popular claims made by some opponents of cannabis reform that regular cannabis use leads to psychosis and other mental health issues.

Full text of the study, “Rates and correlates of cannabis-associated psychotic symptoms in over 230,000 people who use cannabis,” appears in Translational Psychiatry. Additional information on cannabis and mental health is available from NORML’s white paper, ‘Cannabis, Mental Health, and Context: The Case for Regulation.’