[Epidemiology of depression (author's transl)]

The authors use a number of recent studies to illustrate what can be achieved by exemplary work on depression. One of the studies is concerned with incidence in one community and others with comparisons of clinical and psycho-social aspects of depression in different cultures. They underscore the importance of making the distinction between conspicuous and hidden morbidity when measuring morbidity rates. In clinical practice, psychiatrists see only a narrow range of the depressive spectrum, which is made up of many different clinical entities varying in symptomatology and severity. Attempts to compare the prevalence of these conditions are often frustrated by problems of definition and classification of the clearly morbid states, in addition to the difficulties inherent in differentiation between these states and the normally accepted range of mood variations. These points are probably largely responsible for wide differences in the prevalence rates published by different authors and for different countries. The latter part of the discussion emphasizes the scientific importance of transcultural comparisons of depressive symptoms and points out the need to assess the influence of socio-cultural changes upon the frequency and types of depressive states. Throughout all this discussion, the necessity of standardized instruments of clinical assessment is underlined.