A family study of schizoaffective, bipolar I, bipolar II, unipolar, and normal control probands.
In a family study of 1,254 adult relatives of patients and controls, lifetime prevalences of major affective disorder (including schizoaffective) were 37%, 24%, 25%, 20% and 7% in relatives of probands with schizoaffective, bipolar I, bipolar II, and unipolar disease, and normal controls. These data were compatible with the different affective disorders representing thresholds on a continuum of underlying multifactorial vulnerability. In this model, schizoaffective illness represents greatest vulnerability, followed by bipolar I and bipolar II, then unipolar illnesses. Alcoholism, drug abuse, and sociopathy were not more frequent in relatives of patients v relatives of controls. Sex-related transmission of morbid risk was not present. Morbid risk was 74% to offspring of two III parents, and 27% to offspring of one III parent. Nationality and age at time of interview seem to be nongenetic factors that affect frequency of diagnosis.
D000328:Adult; D000367:Age Factors; D000437:Alcoholism / Q000235:genetics; D000987:Antisocial Personality Disorder / Q000235:genetics; D001714:Bipolar Disorder / Q000235:genetics*; D003866:Depressive Disorder / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D010375:Pedigree; D011618:Psychotic Disorders / Q000235:genetics*; D012306:Risk; D012737:Sex Factors; D019966:Substance-Related Disorders / Q000235:genetics