Predicting psychosis in a general adolescent psychiatric sample

Current psychosis risk criteria have often been studied on a pre-selected population at specialized clinics. We investigated whether the Structured Interview for Prodromal Syndromes (SIPS) is a useful tool for psychosis risk screening among adolescents in general psychiatric care.

161 adolescents aged 15-18 with first admission to adolescent psychiatric services in Helsinki were interviewed with the SIPS to ascertain Clinical High-Risk (CHR) state. The participants were followed via the national hospital discharge register, patient files, and follow-up interviews. DSM-IV Axis I diagnoses were made at baseline and 12 months. Register follow-up spanned 2.8-8.9 years, and hospital care for a primary psychotic disorder and any psychiatric disorder were used as outcomes.

CHR criteria were met by 54 (33.5%) of the adolescents. Three conversions of psychosis as defined by SIPS emerged during follow-up, two of whom belonged to the CHR group. The positive predictive value of the CHR status was weak (1.9%) but its negative predictive value was 98.0%. Using the DSM-IV definition of psychosis, there were five conversions, three of which were in the CHR group. In regression analyses, hospital admissions for primary psychotic disorder were predicted by positive symptom intensity in the baseline SIPS. In addition, CHR status and SIPS positive and general symptoms predicted hospitalization for psychiatric disorder.

Psychosis incidence was low in our unselected sample of adolescent psychiatric patients. CHR status failed to predict SIPS or DSM-IV psychoses significantly at 12 months. However, in a longer follow-up, CHR did predict psychiatric hospitalization.