The TRH Test in Psychiatric Disorders

Abstract

The thyrotropin-releasing hormone (TRH) test, that is, measurement of serum levels of thyroid-stimulating hormone (TSH) following TRH administration, is inexpensive, safe, rapidly conducted, depends upon a radioimmunoassay now generally available, and does not require a high level of patient cooperation. It is noteworthy that in psychiatric patients in whom a diminished or blunted TSH response to TRH has been identified, no endocrine explanation has yet been identified. Factors that are known to reduce the TRH-induced TSH response are: increasing age, male sex, acute starvation, chronic renal failure, Klinefelter’s syndrome, repetitive administration of TRH, and administration of somatostatin, neurotensin, dopamine, thyroid hormones, and glucocorticoids (see Loosen 1986, 1988, for a review). Moreover, several drugs can cause abnormal, i.e., attenuated or exaggerated TRH test results (Wenzel 1981; Table 1). These need to be considered whether one performs the TRH test for psychoendocrine purposes or for diagnosis of endocrine disease.