To the Editor.—
Dr Sherman and colleagues1 noted how study design may affect results with the dexamethasone suppression test (DST) in depression. Their observations may explain the 35% to 60% sensitivity in endogenously depressed patients.2 Perhaps every endogenously depressed patient (or even each patient in a larger diagnostic group) is a nonsuppressor, but because of the episodic hormone release we can detect cortisol escape only one time out of two in a single blood sample. One clinical advantage of the DST is its ease of use in outpatients. Blood sampled every 20 minutes is more likely to demonstrate early escape than a single sample and multiple samples have been proposed to increase the sensitivity of the DST.2,3 However, in outpatients, it is difficult to draw blood samples at 4 and 11 PM.
Patients and Methods.—
We have been investigating a more sensitive DST method that is feasible
Charles GA, Wilmotte J, Charles , Rush AJ. A Sensitive, Outpatient Dexamethasone Suppression Test. Arch Gen Psychiatry. 1985;42(5):523-524. doi:10.1001/archpsyc.1985.01790280105013