AFFECTIVE-ILLNESS AND SCHIZOPHRENIA IN FAMILIES WITH MULTIPLE SCHIZOPHRENIC MEMBERS - INDEPENDENT ILLNESSES OR VARIANT GENE(S)

Affective disorder occurs in some families with schizophrenia, and sch izophrenic patients often describe concurrent episode(s) of depression that may lead them to be diagnosed schizoaffective. The present study examines the pattern of affective disorder in families with two or mo re members with schizophrenia or schizoaffective disorder. We find tha t affective disorders are more frequently inherited from the same pare ntal side of the family as schizophrenia-like psychosis. When unipolar , it more often is expressed in female than male relatives (particular ly mothers), and when bipolar it is more likely in males. In contrast, schizophrenia with and without depression is equally prevalent in bot h sexes. Unipolar illness was more common in relatives of schizophreni cs whose illnesses are characterized by recurrent episodes of depressi on than in those whose are not. These data are consistent with the hyp othesis that the same genes could contribute to susceptibility to both schizophrenia and affective disorder in some families, and that sex a nd phenotypic expression are in some way related. However, the phenome non of high rates of depression in mothers of schizophrenic patients n eeds explanation.