Rationale: Some people report that using cannabis helps them cope with negative mental states. This study evaluated effects of cannabis on mental health by assessing whether regular cannabis users are less or more likely to be referred for psychiatric intensive care.

Method: Data was collected from about 52,000 adults across a 15-year period from 4 hospitals. Researchers evaluated whether being referred for psychiatric care, especially during the purported peak period of cannabis withdrawal, was related to cannabis use history.

Results: This study found evidence of significant cannabis withdrawal, peaking 3-5 days after last use. Cannabis users were more likely than non-users (13% vs. 5.3%) to be admitted to psychiatric units while hospitalized. This was especially true in female patients: during the peak withdrawal period nearly 40% were transferred for psychiatric care.

Meaning:  The results of this study, in which cannabis users were more likely to need psychiatric care, suggest that regular cannabis use does not benefit mental health issues. Rather, it may mask them. Upon withdrawal from cannabis, these mental health challenges may require psychiatric care.