Dexamethasone Suppression Test and Diagnosis of Melancholia

Abstract

To the Editor. — The dialogue between Carroll and two alert readers (Archives1981;38:1067-1068) reflects two blind spots in the article on the dexamethasone suppression test (DST): (1) the logical dilemma, as pointed out by Murphy, of comparing a purely clinical descriptive diagnosis (the gold standard) with a newly advocated biologic marker laboratory test, and (2) the insensitivity of the authors, as pointed out by Cochran, to the uselessness of a diagnostic test that is only 50% sensitive. A third blind spot should be emphasized: the gap between the physician of first contact and the scientist at the tertiary center. When Carroll stated that "the routine use of this simple test byu internists, family practitioners, and psychiatrists who treat depressed patients may help to reduce the diagnostic confusion," he confused specificity, sensitivity, and common sense.