Epidemiological perspectives for the development of future diagnostic systems.

Three uses of epidemiological data for diagnostic revisions are suggested. (1) Psychometric analysis of community cases over the full spectrum of symptom severity can help determine whether true discrete disease entities underlie particular symptom profiles. (2) Analysis of external validators in community samples can help select optimal cut-points for defining diagnostic criteria. (3) Clinical epidemiological studies can provide quick and comparatively inexpensive preliminary checks, prior to carrying out expensive experimental treatment trials, on the plausibility of proposed subtyping distinctions based on nonexperimental evidence regarding differential treatment response. Correction of a number of basic conceptual and methodological flaws that have hampered previous studies would allow epidemiological research of these three sorts to play a much more important part in future diagnostic revisions than they have in past revisions. Copyright 2002 S. Karger AG, Basel