This paper examines the intersecting histories of psychiatry and psychology (particularly in its clinical guise) in the United States from the second half of the nineteenth century to the present. It suggests that there have been three major shifts in the ideological and intellectual orientation of the “psy complex.” The first period sees the dominance of the asylum in the provision of mental health care, with psychology, once it emerges in the early twentieth century, remaining a small enterprise largely operating outside the clinical arena, save for the development of psychometric technology. It is followed, between 1945 and 1980, by the rise of psychoanalytic psychiatry and the emergence of clinical psychology. Finally, the re-emergence of biological psychiatry is closely associated with two major developments: an emphasis that emerges in the late 1970s on rendering the diagnosis of psychiatric illnesses mechanical and predictable; and the long-term effects of the psychopharmacological revolution that began in the early 1950s. This third period has seen a shift the orientation of mainstream psychiatry away from psychotherapy, the end of traditional mental hospitals, and a transformed environment within which clinical psychologists ply their trade.