Transition From Substance-Induced Psychosis to Schizophrenia Spectrum Disorder or Bipolar Disorder.
Level 3 - non-randomized controlled study
Nationwide registry-based retrospective cohort study
PubMed 37132221 · doi:10.1176/appi.ajp.22010076
What was done
All patients in the Norwegian Patient Registry diagnosed with substance-induced psychosis between 2010 and 2015 (N=3,187) were analyzed. Cumulative 6-year transition rates to schizophrenia spectrum disorder or bipolar disorder were estimated using the Kaplan-Meier method. Cox proportional hazard regression was used to evaluate the association of transition risks with gender, age, number of emergency admissions for substance-induced psychosis, and type of substance.
What was found
The 6-year cumulative transition rate to schizophrenia spectrum disorder was 27.6% (95% CI=25.6–29.7), six times higher than the transition rate to bipolar disorder at 4.5% (95% CI=3.6–5.5). Transition risk to schizophrenia spectrum disorder was higher among younger men, men with cannabis-induced or polysubstance-induced psychosis, and patients of either gender with repeated emergency admissions. Transition risk to bipolar disorder was higher for women than for men. Numerical hazard ratios were not reported in the abstract.
Why it matters
This nationwide cohort establishes long-term diagnostic conversion rates from substance-induced psychosis, showing that more than one in four individuals convert to schizophrenia spectrum disorders within six years. It identifies clear clinical risk profiles—such as cannabis involvement and recurrent emergency visits—that warrant close psychiatric monitoring.
Limits
The study is observational and relies on administrative health registry diagnoses rather than standardized prospective clinical interviews. Quantitative hazard ratios, confidence intervals for specific predictors, and details on unmeasured confounders (such as family history or baseline symptom severity) were not reported in the abstract.