ICES finds ER visits for substance use linked to higher risk of developing schizophrenia

The study shows people who visit an ER for substance-induced psychoses had an 18.5% risk of developing to schizophrenia within three years of their ER visit. Individuals with an ER visit for substance use without psychosis had a lower 1.4% risk of developing schizophrenia but were still at markedly increased risk relative to the general population, of which 0.1% developed schizophrenia within three years. For individuals with substance-induced psychosis, cannabis had the greatest risk, with 26% of individuals developing schizophrenia within three years - a rate 242 times higher than the general population. Amphetamine use was the highest-risk substance without psychosis, with 3.7% of individuals developing schizophrenia within three years - a rate 28.4 times higher than the general population.