Follow-up studies of schizophrenia have reported divergent rates of outcomes. In addition to definition and measurement challenges, one reason for divergence may be due to sampling biases. Our aim was to report clinical and social outcomes of schizophrenia in the longitudinal, unselected, population-based Northern Finland 1966 Birth Cohort, and describe associated factors.

Subjects with DSM-III-R schizophrenia (N=109) were followed prospectively from mid-pregnancy up to age 35 years. Used outcome measures were positive and negative symptoms, global clinical impression, use of antipsychotics, psychiatric hospitalisations, social and occupational functioning. Several definitions of good and poor outcomes were explored, and predictors of outcomes were analysed.

In a subsample of 59 cases with complete information of outcomes, good clinical outcome varied from 10% to 59%, and good social outcome 15-46%, depending on definition of outcomes. Poor clinical outcome varied 41-77% and poor social 37-54%. Two subjects recovered fully using the most stringent definition of outcome. Lack of friends in childhood, father's high social class, lower school performance and earlier age of illness onset predicted poor outcomes. When the whole sample was considered, early infant development around the age of 1 year was associated with worse course of illness.

Outcomes were heterogeneous and relatively poor in this sample of relatively young schizophrenia subjects. The results were influenced by the definitions and measurements of outcomes. Persons having a sub-optimal developmental trajectory with poor social contacts, poor school performance, and early age of illness onset seem to have the worst outcome.

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.

We report clinical and social outcomes of schizophrenia in the longitudinal, population-based Northern Finland 1966 Birth Cohort, and describe associated demographic, developmental and illness-related factors.

Subjects with DSM-III-R schizophrenia (n = 59) were followed prospectively from mid-gestation up to age 35 years. Outcome measures included positive and negative symptoms, psychiatric hospitalisations, social and occupational functioning. Several definitions of good and poor outcome were explored, and developmental, socio-demographic and clinical predictors of outcomes were analysed.

Good clinical outcome varied from 10% to 59%, and good social outcome 15–46%, depending on definition. Poor clinical outcome varied 41–77% and poor social 37–54%. Lack of friends in childhood, father's high social class, lower school performance and earlier age of illness onset predicted poor outcomes.

The outcomes of schizophrenia in this study depended on definitions used but were relatively poor. The age of illness onset, father's social class, school performance and poor social contacts in childhood were only statistically significant predictors.

Definitions of outcome have a major effect on estimates for proportions of good and bad outcomes and on the predictors of outcomes. However, regardless of which definitions were used, the outcome of schizophrenia in this population-based sample was generally bleak.