Childhood developmental abnormalities in schizophrenia: evidence from high-risk studies.

According to cohort studies, individuals who develop schizophrenia in adulthood show developmental abnormalities in childhood. These include delays in attainment of speech and motor milestones, problems in social adjustment, and poorer academic and cognitive performance. Another method of investigating developmental abnormalities associated with schizophrenia is the high-risk (HR) method, which follows up longitudinally the development of children at high risk for schizophrenia. Most HR studies have investigated children who have a parent with schizophrenia. This review summarizes findings concerning childhood and adolescent development from 16 HR studies and compares them with findings from cohort, conscript, and family studies. We specifically addressed two questions: (1) Does the development of HR children differ from that of control children? (2) Which developmental factors, if any, predict the development of schizophrenia-spectrum disorders in adulthood? While the answer to the first question is affirmative, there may be other mechanisms involved in addition to having a parent with schizophrenia. Factors which appear to predict schizophrenia include problems in motor and neurological development, deficits in attention and verbal short-term memory, poor social competence, positive formal thought disorder-like symptoms, higher scores on psychosis-related scales in the MMPI, and severe instability of early rearing environment.