DST and TRH stimulation test in mood disorder subtypes

Both the dexamethasone suppression test (DST) and the thyrotropin-releasing hormone (TRH) stimulation test have been reported to be useful in subtyping some depression diagnoses. Whether the DST discriminates delusional from nondelusional depression remains controversial, but this possibility has not been studied for the TRH test. The authors evaluated DST and TRH test results in 29 depressed hospitalized patients; both tests significantly discriminated patients with nonendogenous depression from those with endogenous depression. Furthermore, postdexamethasone cortisol levels but not the change in thyroid-stimulating hormone discriminated the patient with endogenous delusional depression from those with endogenous nondelusional depression.