Developmental precursors of psychosis.

Subtle developmental (motor, emotional, cognitive, and behavioral) abnormalities are often present in apparently healthy individuals who later develop psychosis, suggesting that some aspects of causation are established before overt psychosis. These impairments may restrict information processing and social achievements years before manifesting psychosis. The main known risk factors in the development of schizophrenic psychosis are genetic factors, pregnancy and delivery complications, slow neuromotor development, and deviant cognitive and academic performance. However, their effect size and predictive power are small. Developmental precursors are not necessarily specific to schizophrenia, but also common to other psychotic disorders. No powerful risk factor, premorbid sign, or risk indicator has been identified that is useful for prediction of psychoses in the general population.