The Group of Schizophrenias, Schizoaffective Psychoses, and Affective Disorders

A family genetic study of a sample of 269 probands with functional psychoses and 1,577 first-degree relatives is reported. The diagnostic distinction between schizophrenia and affective psychoses tended to be confirmed by the finding that approximately 10 percent of the first-degree relatives of probands with schizophrenia or affective psychoses suffered from the same disorder as the proband. By comparison, the incidence of affective psychoses in relatives of probands with schizophrenia, and of schizophrenia in relatives of probands with affective psychoses, was 4 percent and 3 percent, respectively. When schizophrenic probands were further divided by subtype diagnosis, the highest rate of global schizophrenia was found in relatives of catatonics (13 percent), hebephrenics (8 percent), and paranoid schizophrenics (7 percent). With regard to subtype diagnoses, there was also a tendency toward homotypical secondary cases among relatives of probands with these three subtype diagnoses. Catatonia, in addition to being characterized by the highest global schizophrenia risk and the most prominent homotypical morbidity, was also associated with a relatively high rate of secondary cases with affective psychoses. The relatives of schizoaffective probands showed the highest overall frequency of functional psychoses (23 percent), with schizophrenic and affective-psychotic secondary cases being equally frequent, and no marked homotypical morbidity for the schizoaffective subtype diagnosis itself. Probands with affective psychoses of all types were found to have a high rate of unipolar secondary cases among their relatives. Bipolar affective disorder did not show a marked homotypical morbidity in this sample.