Predicting psychosis and psychiatric hospital care among adolescent psychiatric patients with the Prodromal Questionnaire.

The Prodromal Questionnaire (PQ) identifies psychiatric help-seekers in need of clinical interviews to diagnose psychosis risk. However, some providers use the PQ alone to identify risk. Therefore, we tested its predictive utility among 731 adolescent psychiatric help-seekers, with a 3-9-year register-based follow-up. Nine latent factors corresponded well with postulated subscales. Depersonalization predicted later hospitalization with a psychosis diagnosis (HR 1.6 per SD increase), and Role Functioning predicted any psychiatric hospitalization (HR 1.3). Published cut-off scores were poor predictors of psychosis; endorsement rates were very high for most symptoms. Therefore, we do not recommend using the PQ without second-stage clinical interviews.