A recent systematic review of longitudinal studies of cannabis use and subsequent psychotic outcomes reported a 40% increased risk of psychotic outcome in individuals who had ever used cannabis (pooled adjusted OR = 1.41, 95% CI 1.20 ± 1.65) [160]. The risk rose in a dose-dependent fashion with greater cannabis exposure (OR = 2.09, 1.54 ± 2.84). Meta-analyses suggest that cannabis might account for between 8 and 14% of schizophrenia cases [93, 160].
