Morning and evening TSH response to TRH and sleep EEG disturbances in major depressive disorder

1. The aim of this study was to investigate hypothalamo-pituitary-thyroid a xis (HPTA) functioning and sleep EEG disturbances in major depressive disor der. 2. Thyroid function was evaluated by determination of TSH levels before and after 8 AM and 11 PM TRH administration on the same day in a sample of 113 consecutively-admitted DSM-IV major depressed inpatients (72 females aged 44.3 +/- 13.0 and 41 males aged 45.7 +/- 10.7) that underwent sleep EEG rec ordings. 3. A blunted TSH response occurred in 15.9 % for 8 AM Delta TSH (maximum in crement above baseline at the 8 AM TRH challenge), in 39.8 % for 11 PM Delt a TSH and in 77 % for MTSH (difference between 11 PM Delta TSH and 8 AM Del ta TSH). A negative correlation between Delta Delta TSH and duration of awa kenings after sleep onset, and a shorter sleep onset latency in patients wi th a blunted 11 PM Delta TSH were found, but these two significant relation ships disappeared after controlling for the effects of gender and age. 4. The present findings do not support the hypothesis that, in major depres sion, HPTA dysfunctioning, as reflected in TSH response to TRH, may be rela ted to sleep EEG disturbances.