Twenty‐four‐hour serum levels of T₄ and T₃ in relation to decreased TSH serum levels and decreased TSH response to TRH in affective disorders

Abstract

The serum levels of thyroxine and triiodothyronine (T4 and T3) were investigated at 10 different time points during a 24 h period in 31 inpatients meeting the RDC criteria for acute major depressive disorder. Twenty-three of these patients were also reinvestigated in a state of partial or complete remission. The results show that there was no significant difference in T4 or T3 levels during the 24 h period between depressed patients and 32 healthy controls despite significantly decreased TSH levels and TSH response to TRH administration (delta TSH) in the patient group. No indications were obtained that the patients' clinical presentation or depressive symptomatology as revealed by their CPRS scores, psychotropic medication, melatonin levels, or the outcome of the dexamethasone test, significantly influenced the T4 or T3 levels. The depressed patients who were studied longitudinally showed increased T4 levels in the acute phase compared to remission, whereas the T3 levels did not change. However, the levels of thyroid hormones were within the normal range in the acute phase as well as in remission. Furthermore, the changes in thyroid hormones between the state of relapse and remission were not significantly correlated to the corresponding increase in TSH levels and delta TSH between the two assessments. The present results are consistent with the hypothesis that the mechanism behind the impaired TSH response to TRH in acute major depressive disorder is a downregulation of the pituitary TRH receptors.

Serum Concentrations of Circulating Thyroid Hormones in a Group of Depressed Men

“…This is similar to the findings of Linnoila et al [2] and Orsulak et al [4], On the other hand, other studies on T3 in depressed patients reported it normal [3,9], Furthermore, Spratt et al [10] reported increased T3 and T4 levels in a series of 646 psychiatric patients that included depressed subjects.…”

Thyroid Allostasis–Adaptive Responses of Thyrotropic Feedback Control to Conditions of Strain, Stress, and Developmental Programming

“…Concentrations of T4 or FT4 are commonly increased during depression (324–329) and revert after recovery from MD, irrespective of the modality of treatment (330–339). Despite the presence of elevated T4 concentrations TSH levels tend to be normal in depressive patients, but circadian variation of TSH concentration is impaired (339–342) and the response to TRH test is blunted (323). Both total and free T3 concentrations are reduced in MD (175, 176, 343), but elevated in bipolar I disorder (237, 344).…”

Thyroid response to dexamethasone: A study on normal controls and patients with psychogenic sexual dysfunction: Der Einfluß von Dexamethason auf die Schilddrüsenfunktion bei Patienten mit erektiler Dysfunktion und gesunden Männern

“…Concerning reports on the response of prolactin to dexamethasone administration (Rupprecht et al -1988) describing endocrine as well as clinical similarities between minor depression and psychosexual dysfunction, this study reveals comparable results on thyroid hormones. In patients with major depression some authors noted lower (Orsulak et al -1985) or normal T, and normal T4 levels (Unden et al -1986) as well as decreased levels of TSH (Unden et al -1986).…”

“…During depression normal (Unden et al 1986) or lowered T3 levels (Orsulak et al -1985) and lowered TSH levels (Unden et al -1986) were reported. More consistent, however, is the blunted response of TSH to TRH depending on the depressive state (Agren and Wide -1986).…”