Neuroendocrine abnormalities in affective disorders

The authors review neuroendocrine abnormalities in depression, and present data on the thyrotropin-releasing hormone (TRH) test in unipolar depression. Sixty of 105 patients who met Research Diagnostic Criteria for major unipolar depression had a blunted thyroid-stimulating hormone (TSH) response to TRH as defined as by delta TSH less than 7.0 micro IU/ml. Only 4 of 40 patients with non-major depression and 0 of 20 normal controls had a blunted TSH response to TRH by this criteria. Of 50 unipolar patients administered both the TRH test and the dexamethasone suppression test (DST), 34% were identified by the TRH test only, 20% by the DST only, 30% by either test, and 15 by neither test. The TRH test and DST seem to be complementary in the neuroendocrine evaluation of the patient with possible unipolar depression. The TRH test along with other neuroendocrine tests may be of help to the clinician in the diagnosis of depression and in treatment planning.