Question: What is the risk of developing schizophrenia spectrum disorder following an emergency department (ED) visit caused by substance use with and without psychosis?
Findings: In this cohort study of 9.8 million people, individuals with an ED visit for substance-induced psychosis or substance use without psychosis were at increased risk of developing schizophrenia spectrum disorder within 3 years relative to the general population.
Meaning: These findings suggest that people who present to the ED for substance use, with or without psychosis, are at increased risk of developing schizophrenia spectrum disorder.
Abstract
Importance: Episodes of substance-induced psychosis are associated with increased risk of developing a schizophrenia spectrum disorder. However, there are limited data on the transition risk for substance use without psychosis.
Objectives: To quantify the risk of transition to schizophrenia spectrum disorder following an incident emergency department (ED) visit for (1) substance-induced psychosis and (2) substance use without psychosis and to explore factors associated with transition.
Results: The study included 9 844 497 individuals, aged 14 to 65 years (mean [SD] age, 40.2 [14.7] years; 50.2% female) without a history of psychosis. There were 407 737 individuals with an incident ED visit for substance use, of which 13 784 (3.4%) ED visits were for substance-induced psychosis. Individuals with substance-induced psychosis were at a 163-fold (age- and sex-adjusted hazard ratio [aHR], 163.2; 95% CI, 156.1-170.5) increased risk of transitioning, relative to the general population (3-year risk, 18.5% vs 0.1%). Individuals with an ED visit for substance use without psychosis had a lower relative risk of transitioning (aHR, 9.8; 95% CI, 9.5-10.2; 3-year risk, 1.4%), but incurred more than 3 times the absolute number of transitions (9969 vs 3029). Cannabis use had the highest transition risk among visits with psychosis (aHR, 241.6; 95% CI, 225.5-258.9) and the third-highest risk among visits without psychosis (aHR, 14.3; 95% CI, 13.5-15.2). Younger age and male sex were associated with a higher risk of transition, and the risk of male sex was greater in younger compared with older individuals, particularly for cannabis use.
Conclusions and Relevance: The findings of this cohort study suggest that ED visits for substance use were associated with an increased risk of developing a schizophrenia spectrum disorder. Although substance-induced psychoses had a greater relative transition risk, substance use without psychosis was far more prevalent and resulted in a greater absolute number of transitions. Several factors were associated with higher transition risk, with implications for counseling and early intervention
(Source: JAMA Psychiatry | JAMA Network 2023)