The TRH-test in depression: a review

The TRH-test in depression: a review This paper reviews the literature on the thyrotropin releasing hormone (TRH)-test in depressive patients. The TRH-test appears to exhibit some use as an external validating criterion for the clinical diagnosis of major depression and, in particular melancholia versus minor depression once the clinical diagnosis depression is made. However, the clinical use of this test is hampered by the low sensitivity (±50%) and by the fact that abnormal tests occur in non-depressive states such as borderline personality disorder, schizophrenia, and anxiety disorders. The TRH-test may be used as a predictor for a positive response to biological therapies. In addition, the test has some value for the outcome of a depressive episode. The pathophysiology underpinning an abnormal TRH-test may be determined by noradrenergic (central and peripheric) or serotonergic (central) dysfunctions, thyroid hormone and cortisol hypersecretion, phenomena that are pertinent to severe depression. Recently, it has been established that an abnormal depression-linked TRH-test reflects lower basal thyroid secreting hormone (TSH) secretion. The determination of basal TSH may, in the future, replace TRH-testing.