Amish Study, I: Affective disorders among the Amish, 1976-1980.

The authors review the goals, methods, sample, and selected epidemiologic findings from a collaborative study of affective disorders among the Amish. This culturally and genetically homogeneous population (N = 12,500) constitutes an excellent research setting for psychiatric epidemiologic and genetic study. Alcoholism, drug abuse, and sociopathy did not complicate the study because they are culturally prohibited. During 1976-1980, 112 active cases of mental illness were identified; 71% received diagnoses of major affective disorder. Equal numbers of men and women received diagnoses of unipolar illness, and slightly more men than women were diagnosed as having bipolar illness.