Temperature circadian rhythms during the menstrual cycle and sleep deprivation in premenstrual dysphoric disorder and normal comparison subjects

The aim of this study was to test the hypothesis that the circadian rhythm of core body temperature is altered in premenstrual dysphoric disorder (PMDD) subjects compared to that in normal comparison (NC) subjects and that it is normalized in PMDD subjects after treatment with early night partial sleep deprivation (ESD) or late night partial sleep deprivation (LSD). A total of 23 subjects meeting DSM-IV criteria for PMDD and 18 NC subjects had 24-h core body temperature recordings taken during the following conditions: (1) baseline midfollicular (preovulatory) and (2) late luteal (postovulatory) menstrual cycle phases and after a randomized crossover trial in subsequent luteal phases of (3) ESD, in which subjects slept from 03:00 to 07:00 h, followed by (4) a night of recovery sleep (ESD-R: sleep 22:30 to 06:30 h), and (5) LSD, in which subjects slept from 21:00 to 01:00 h, also followed by (6) a night of recovery sleep (LSD-R: sleep 22:30 to 06:30 h). Temperature amplitudes were significantly decreased in the luteal phase compared to those in the follicular menstrual cycle phase and increased after nights of recovery sleep. Compared to the baseline late luteal phase, during LSD, temperature amplitude increased in PMDD subjects but decreased in NC subjects. During ESD, the temperature acrophase was delayed in PMDD subjects but was advanced in NC subjects; during LSD, the temperature acrophase was advanced in PMDD subjects but was delayed in NC subjects compared to the late luteal baseline. Nocturnal temperature and temperature maxima and mesors tended to be higher in PMDD subjects than in NC subjects; when not reduced during sleep deprivation interventions, these were not associated with therapeutic effects. Alterations in both phase and amplitude of temperature circadian rhythms characterize PMDD subjects as contrasted with NC subjects in response to sleep deprivation. The changes in phase reflected more shifts in temperature acrophase in response to shifts in sleep in PMDD subjects. This realignment of the timing of sleep and temperature in addition to the enhancement of blunted amplitude rhythms during recovery nights of sleep may provide corrective mechanisms that contribute to the therapeutic effects of sleep deprivation.