Precursors to schizophrenia: Do biological markers have specificity?

This review addresses childhood antecedents and biological markers of schiz ophrenia within a neurodevelopmental framework. General-population birth-co hort studies illustrate delays in developmental milestones, abnormalities i n social functioning, and cognitive deficits throughout childhood, adolesce nce and early adulthood. Abnormal neurology and motor dysfunction have been measured in children prior to the onset of schizophrenia, at first onset o f disease, and in those with chronic schizophrenia. Minor physical anomalie s, a static marker of developmental disturbance, are also increased in schi zophrenia. None of these factors has high specificity for this disorder. This review examines the associations between these precursors and some eti ological factors for schizophrenia, comments on their lack of complete spec ificity to this psychotic syndrome, and considers their usefulness as predi ctors of risk.