TSH Responses to TRH as a Function of Basal Serum TSH: Relevance for Unipolar Depression in Females - A Multivariate Study

Abstract

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.

Thyroid and adrenal axis in major depression: a controlled study in outpatients

“…However, neither serum cortisol nor urinary cortisol was related to serum TSH levels in the present study. This is in line with another study reporting no relation between baseline serum cortisol and serum TSH in depressed inpatients (49).…”

The prevalence of affective disorder and in particular of a rapid cycling of bipolar disorder in patients with abnormal thyroid function tests

“…It has been reported that antithyroid antibodies occur at a rate of up to 20% in psychiatric patients with affective symptoms (Haggerty et al, 1990). Raised TSH levels were also found more frequently in patients with affective symptoms (Maes et al, 1992;Tappy et al, 1987). These observations have been presented as evidence that subclinical autoimmune hypothyroidism may be a specific risk factor for the development of an affective disorder (Haggerty et al, 1993).…”

A Case Report Showing that Subclinical Hypothyroidism Rather than Hyperthyroidism Stabilizes Rapidly Cycling Bipolar Illness

“…Among the first studies using the ultrasensitive TSH measure in depressed patients, Maes et al [4] found a negative correlation before treatment between the Hamilton Depression Scale and TSH. In their review, Fava et al [5] also found evidence for an association between hyperthyroidism and depression.…”