A family study of the subtypes of schizophrenia.

The authors conducted a blind family study based on probands diagnosed as schizophrenic by DSM-III and subtyped by four diagnostic systems. The pattern of psychopathology in relatives did not differ as a function of the probands' subtype diagnosis. Relatives of paranoid and nonparanoid schizophrenic probands had similar risks for schizophrenia and affective illness. Resemblance in subtype diagnosis between probands and their affected relatives did not exceed chance expectation. The etiologic role of familial factors appears to be similar in each of the traditional subtypes of schizophrenia. No evidence was found for familial factors specific for individual subtypes.