Collaboration between sociology and psychiatry is traced to the 1920s when, stimulated by Harry Stack Sullivan and Adolph Meyer, the relationship was activated by common theoretical and research interests. Immediately after World War II, this became a true partnership, stimulated by the National Institute of Mental Health, the Group for the Advancement of Psychiatry, and the growing influence of psychoanalytic theory. The effects of a sociology that focused on issues of health and illness proceeded to grow in medical education, research, and the treatment of mental illness until 1980, when a distinct shift of emphasis in psychiatry occurred. In its role as educator of future physicians, postwar psychiatry developed a paradigm of biopsychosocial behavior but, after 3 decades, changed to a biopharmacological model. The definition of mental illness as a deviant extreme in developmental and interpersonal characteristics lost favor to nosological diagnoses of discrete or dichotomous models. Under a variety of intellectual, socioeconomic, and political pressures, psychiatry reduced its interest in and relationship with sociology, replacing it in part with bioethics and economics. In this article, the detailed underpinnings of these changes are described and interpreted.