Precursors to schizophrenia: Do biological markers have specificity?

This review addresses childhood antecedents and biological markers of schizophrenia within a neurodevelopmental framework. General-population birth-cohort studies illustrate delays in developmental milestones, abnormalities in social functioning, and cognitive deficits throughout childhood, adolescence and early adulthood. Abnormal neurology and motor dysfunction have been measured in children prior to the onset of schizophrenia, at first onset of disease, and in those with chronic schizophrenia. Minor physical anomalies, a static marker of developmental disturbance, are also increased in schizophrenia. None of these factors has high specificity for this disorder. This review examines the associations between these precursors and some etiological factors for schizophrenia, comments on their lack of complete specificity to this psychotic syndrome, and considers their usefulness as predictors of risk.