TSH responses to TRH as a function of basal serum TSH: relevance for unipolar depression in females--a multivariate study.
Baseline thyroid-secreting-hormone (TSH)-assessed by means of ultrasensitive assays (IRMA)-and free-thyroid-hormone (FT4) levels were determined in 84 depressed females, and the TSH responses to 200 micrograms thyrotropin-releasing hormone (TRH) (IV) measured. It was found that TRH-induced TSH responses were linearly and positively related to basal TSH-IRMA; lower TRH-stimulated TSH secretion in melancholic patients was attributable to lowered basal TSH-IRMA values. A progression was found-within the euthyroid range-of basal TSH-IRMA values towards lower levels along the diagnostic spectrum: the highest basal TSH-IRMA levels were witnessed in minor depressives and the lowest in melancholics, while simple major-depressed females occupied an intermediate position. This shift appears to be indicative of severity of illness. Basal TSH-IRMA data can roughly be used as a clinical tool separating melancholia from minor depression: at a threshold value of less than or equal to 1 microUI/ml, sensitivity was 56% and specificity 92%. It is concluded that basal TSH-IRMA provides a more accurate representation of melancholia than peak TSH responses, which appear to constitute little more than a magnified, but biased signal of basal TSH-IRMA. In future, the assay of basal TSH-IRMA could replace TRH testing.
Maes
M
M
Department of Psychiatry, University of Antwerp, Belgium.
Schotte
C
C
Vandewoude
M
M
Martin
M
M
Blockx
P
P
D000375:Aging / Q000378:metabolism; D003866:Depressive Disorder / Q000097:blood* / Q000523:psychology; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D010363:Pattern Recognition, Automated; D011569:Psychiatric Status Rating Scales; D013972:Thyrotropin / Q000097:blood*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D013973:Thyrotropin-Releasing Hormone; D013972:Thyrotropin