The Continuum of Depressive States in the Population and the Differential Diagnosis Between “Normal” Sadness and Clinical Depression

Abstract

One of the principles of the “neo-kraepelinian credo”, articulated in the 1970s, was that “there is a boundary between the normal and the sick”. In other terms, it was maintained that there is a clear, qualitative distinction between persons who have a mental disorder and persons who do not. A corollary to this principle was the statement that “depression, when carefully defined as a clinical entity, is qualitatively different from the mild episodes of sadness that everyone experiences at some point in his or her life”. Apparently in line with this statement was the observation that tricyclic antidepressants were active only in people who were clinically depressed; when administered to other people, they did not act as stimulants nor did they alter the subjects’ mood. Today the picture has changed dramatically. Taxonomic studies have failed to support the idea that a latent qualitative difference exists between major depression and ordinary sadness, arguing instead in favor of a continuum of depressive states in the general population. We are left, therefore, with two competing approaches: a “contextual” approach, which assumes that the differential diagnosis between “true” depression and “normal” sadness should be based on the presence or not of a triggering life event and on whether the response is proportionate to that event in its intensity and duration; and a “pragmatic” approach, positing that the boundary between depression and “normal” sadness should be based on issues of clinical utility (i.e., thresholds should be fixed – in terms of number, intensity and duration of symptoms, and degree of functional impairment – which are predictive of clinical outcomes and treatment response). This chapter summarizes the strengths and weaknesses of these two approaches.