This paper provides a conceptual framework for understanding the relationship of psychiatry, epidemiology, and sociology. After a section on definitions, seven empirical contributions by sociologists to the field of psychiatric epidemiology are briefly presented to illustrate the notion of the social fact (contributions by Durkheim, Dunham, Hollingshead, Srole and Langner, Kerckhoff and Back, Dohrenwend, and Brown). Four broad sociological theories are reviewed, as illustrations of the sociological imagination (stratification theory, the idea of Verstehen, symbolic interactionism, and the sociology of knowledge). It is concluded that two major contributions of sociology to psychiatric epidemiology are the concepts and data related to the social fact, and the possibilities offered by the sociological imagination.