To the Editor.
—The DST is an important development in the diagnostic approach to depression. After Dr Carroll's original publication (Archives 1981;38:15-22), correspondence from Drs Murphy and Cochran expressed concern about the diagnostic value of the DST and its application to populations with a prevalence differing from Dr Carroll's original patient group. The results of the following study should be of interest.Fifteen psychiatry residents at a univesity teaching program completed the following questionnaire related to the DST: The DST in your facility has been shown to be 70% sensitive and 95% specific. The test will be applied to a large group of psychiatric patients where the prevalence of endogenous depression is 1%. If the test is positive in an individual patient, what is your diganostic confidence that the patient has endogenous depression?