Relationships between Thyroid Hormone and Antidepressant Responses to Total Sleep Deprivation in Mood Disorder Patients

Background: Acute transient antidepressant effects of sleep deprivation are consistently observed in 50% of depressed patients, but the mechanisms of these, at times, dramatic improvements in mood have not been adequately elucidated. Some, but not all, studies suggest a relationship to increased thyroid-stimulating hormone (TSH) secretion. Methods: TSH and other thyroid indices were measured at 8:00 after a baseline night’s sleep and at 8:00 following a night of total sleep deprivation (S.D.) in 34 medication-free, affective disorder patients assessed with Hamilton, Beck, and Bunney–Hamburg depression ratings as well as two hourly self-ratings on a visual analog scale. Results: Compared with baseline, S.D. induced highly significant increases in TSH, levothyroxine, free levothyroxine, and triiodothyronine. The 12 S.D. responders tended to have greater TSH increases than the 15 nonresponders (p< .10). The change in Beck depression ratings significantly correlated with the change in TSH (r = −.40, p = .0496, n = 24). Conclusions: These data are consistent with several other reports of a significant relationship between degree of antidepressant response to S.D. and increases in TSH measured at 8:00 near their usual nadir. Acute removal of the sleep-related break on the hypothalamic–pituitary–thyroid axis remains a promising candidate for the mechanism of sleep deprivation-induced improvement in mood in depressed patients.