Transmitted factors in the morbid risk of affective disorders: A controlled study

Data on psychiatric disorders were collected on first-degree relatives and spouses of 70 patients with primary affective disorder and 75 patients admitted to a general hospital without psychiatric disorder, from the Jewish population of Jerusalem, Israel. Bipolar patients tended to have more bipolar relatives than unipolar patients, but unipolar patients had an observable morbid risk for bipolar disorder in their relatives. Ethnicity and age of onset did not appear to be related to transmissible factors in the prevalence of affective disorders in relatives, although age of onset was associated with morbid risk. Sex-linkage or genetic liability to affective disorder related to sex did not appear to be present. A spectrum of related disorders for this population was defined by those disorders which were more prevalent in relatives of affective disorder patients than in relatives of controls. Assortative mating was not found, but a modest degree of inbreeding appeared to be present. For purposes of testing liability-threshold models for genetic factors in the transmission of mood disorders, only the data on polarity seems suitable.