Thyroid Function and Partial Sleep Deprivation Response

To the Editor.—  Baumgartner et al^1,2 have recently documented higher thyroxine, free thyroxine, and reverse triiodothyronine levels in patients with depression who responded to total sleep deprivation (TSD) vs nonresponders.Sleep deprivation, both partial and total, remains the only antidepressant intervention with a same-day beneficial effect. Originally reported by Pflug and Tolle, the antidepressant effects of one night of TSD have subsequently been confirmed in more than five dozen studies.^3,4 Partial sleep deprivation (PSD), which involves awakening the subject at 2 AM, appears to produce similar effects.⁵ Partial sleep deprivation is a more tolerable procedure for the patient and, therefore, may be preferable to TSD. To date, however, there have been no direct comparative trials between PSD and TSD. While two other manipulations of the sleep-wake cycle (phase-advance of the sleep period and selective rapid eye movement deprivation) have been shown to improve major depression symptoms,