Subtle motor, emotional, cognitive and behavioral abnormalities are often present in apparently healthy children and adolescents who later develop schizophrenia. This suggests that some aspects of causation are established long before psychosis is manifest. We aim to develop a descriptive model of the factors contributing to the development of schizophrenia. Our main focus is on genetic factors, pregnancy and delivery complications, early development and scholastic performance. This is done by reviewing the Northern Finland 1966 Birth Cohort, its scientific activities (publications and work in progress) and selected literature.