In a Norwegian study, patients with substance-induced psychosis were 6 times more likely to transition to schizophrenia spectrum disorder than to bipolar disorder. “Gender, age, number of emergency admissions, and type of substance-induced psychosis affected the risk of transition,” the authors conclude.
The analysis included all patients in the Norwegian Patient Registry with a diagnosis of substance-induced psychosis from 2010 to 2015 (N = 3,187). The Kaplan-Meier and Cox proportional hazard regression yielded these hazard ratios for transitions to schizophrenia spectrum or bipolar disorders: “The 6-year cumulative transition rate from substance-induced psychosis to schizophrenia spectrum disorder was 27.6% (95% CI = 25.6–29.7). For men, the risk of transition was higher among younger individuals and those with either cannabis-induced psychosis or psychosis induced by multiple substances; for both genders, the risk of transition was higher among those with repeated emergency admissions related to substance-induced psychosis. The cumulative transition rate from substance-induced psychosis to bipolar disorder was 4.5% (95% CI = 3.6–5.5), and the risk of this transition was higher for women than for men.”