Risk-thresholds for the association between frequency of cannabis use and the development of psychosis: a systematic review and meta-analysis
Psychological Medicine March 24, 2022 Tessa Robinson, Muhammad Usman Ali, Bethany Easterbrook et al. 61 citations
A meta-analysis of ten studies (three cohort, seven case-control) with 7,390 participants aged 12–65 found a log-linear dose-response association between cannabis use frequency and psychosis risk. The risk of psychosis significantly increased with weekly or more frequent use: weekly use showed a relative risk of 1.35 (95% CI 1.19–1.52) and daily use a relative risk of 1.76 (95% CI 1.47–2.12). Less frequent use (yearly or monthly) was not associated with a significant increase in risk. The authors conclude that frequent cannabis users are at increased risk of psychosis and recommend public health messages convey these risk thresholds.