Thyroid hormones in major depressive disorder and bipolar disorder

Serum Thyrotropin Concentrations and Bioactivity During Sleep Deprivation in Depression

“…56,57 However, the combination of increased serum thyrotropin level and normal serum thyroid hormone levels may explain the proposed association between MDD and subclinical primary hypothyroidism. [12][13][14] Our results do not indicate central (ie, hypothalamic) hypothyroidism, which is typified by high serum thyrotropin concentrations, low serum thyroid hormone levels, an exaggerated response to protirelin, low thyrotropin B/I, and high serum concentrations of free thyrotropin-␤ subunit. [58][59][60][61] Our responders' thyrotropin-␣ and thyrotropin-␤ subunit concentrations and thyrotropin-␤/thyrotropin-␣ ratios were not different from those of nonresponders or controls.…”

“…Female responders had higher thyrotropin levels (6. 45 13.76 = 3.63; P = .054; 2-way design group, F 2,7.57 = 3.15; P = .10) (control mean, 1.74±0.45). No main effects or interactions involving sex were found in the 2-way analyses (sex main effect, F 1,9.16 =0.006; P=.94; groupϫsex interaction, F 2,7.57 =2.18; P =.18).…”

“…[6][7][8][9] Alterations in hypothalamic-pituitary-thyroid axis (HPT) function may be involved in MDD. [10][11][12][13] Major depressive disorder is common in hypothyroid patients, 10 and some [12][13][14] but not all 15,16 studies indicate that some patients with MDD have subclinical primary hypothyroidism. However, rather than having the exaggerated thyrotropin response to protirelin characteristic of hypothy-roidism, about 30% of depressed euthyroid patients have blunted responses to protirelin.…”