HYPOTHALAMIC-PITUITARY-THYROID-AXIS FUNCTION IN TREATMENT-RESISTANT DEPRESSION

Recently, there were some reports that the prevalence of various grade s of hypothyroidism may be increased in patients with treatment resist ant depression (TRD). The aim of the present study was to examine seru m basal thyroid-stimulating hormone (TSH) and thyroxine (T4) levels in 36 major depressed subjects, of whom 27 had TRD and 15 were normal vo lunteers. There were no significant differences in serum basal TSH or T4 levels between major depressed subjects and normal controls, or bet ween patients with TRD versus normal controls or subjects without TRD. There was a trend towards lower serum basal T4 concentrations in pati ents with TRD than in other depressed patients and normal controls. On e patient with TRD had basal serum TSH levels in the hyperthyroid rang e. Two subjects, one with TRD and one normal control, had serum TSH va lues in the subclinical hypothyroid zone, but their serum T4 values we re in the euthyroid range. There were no significant relationships bet ween basal TSH or T4 and severity of illness, staging of depression ba sed on prior treatment non-response, length of the depressive episode, duration of illness, or number of previous depressive episodes. In co nclusion, the results of this study do not provide evidence that (subc linical) hypothyroidism occurs more than coincidentally in depressed p atients with TRD. (C) 1997 Elsevier Science B.V.