Subjects with family history of psychosis and with prodromal symptoms are at risk for schizophrenia. The aim was to study whether adolescents with familial risk have more commonly prodromal features.

Members (N= 9,215) of the Northern Finland 1986 Birth Cohort, an unselected general population cohort, were invited to participate in a field survey conducted during 2001-2002. At the ages of 15-16 years, the study included a 21-item PROD-screen questionnaire developed for screening prodromal psychotic symptoms with 12 specific questions for psychosis (Heinimaa et al. 2003). The scale measured symptoms for last six months. The Finnish Hospital Discharge Register was used to find out parental psychoses during 1972-2000.

Of the males 24% and 37% of the females were screen positives for prodromal features at the age of 15-16 years. Of the offspring, 1.8% had parents with psychosis. The prevalence of screen positives was 26% in males and 36% in females with familial risk for psychosis.

Prodromal features of psychosis are prevalent in adolescence. It may be difficult to screen adolescent subjects at risk for developing schizophrenia with a questionnaire in a general population, especially as these symptoms do not appear to be more common among subjects with familial risk.

The Academy of Finland, the National Institute of Mental Health, the Signe and Ane Gyllenberg Foundation and the Thule Institute, Finland.