Genetics of affective disorders. II. Morbidity risk and genetic transmission.

Morbidity risk and genetic transmission data on a small population of bipolar, unipolar and schizo-affective outpatients suggest a possible genetic overlap between bipolar and schizo-affective patients. There is a conspicuous absence of a homologous illness in the relatives of schizo-affective probands, although the incidence of schizophrenia was higher in these relatives as compared to the relatives of either bipolar or unipolar probands. The data, although tentative because of the relatively small numbers involved, suggest a multifactorial mode of transmission in some affective illnesses.

Genetics of affective disorders. I. Familial incidence study of bipolar, unipolar and schizo-affective illnesses.

47 affectively ill psychiatric patients and their first-, second- and third-degree relatives were investigated by means of an interview and pedigree analysis to determine the incidence of psychiatric illness in their families. The percentage of psychiatric illness appeared greatest in families of bipolar and schizo-affective probands and least in families of unipolar depressives. In addition, we observed that often within a particular family constellation, more than one type of psychiatric illness (i.