Predictors of schizophrenia: evidence from the Northern Finland 1966 Birth Cohort and other sources.

BACKGROUND Subtle motor, emotional, cognitive and behavioural abnormalities are often present in apparently healthy individuals who later develop schizophrenia, suggesting that some aspects of causation are established before overt psychosis. AIMS To outline the development of schizophrenia. METHOD We drew on evidence from The Northern Finland 1966 Birth Cohort supplemented by selected findings from other relevant literature. RESULTS The main known risk factors in development of schizophrenia are genetic causes, pregnancy and delivery complications, slow neuromotor development, and deviant cognitive and academic performance. However, their effect size and predictive power are small. CONCLUSIONS No powerful risk factor, premorbid sign or risk indicator has been identified that is useful for the prediction of schizophrenia in the general population.