Nocturnal polysomnographic sleep across the menstrual cycle in premenstrual dysphoric disorder.

OBJECTIVES: Women with premenstrual dysphoric disorder (PMDD) experience disturbed mood, altered melatonin circadian rhythms, and frequent reports of insomnia during the luteal phase (LP) of their menstrual cycle. In this study we aimed to investigate nocturnal polysomnographic (PSG) sleep across the menstrual cycle in PMDD women and controls.

METHODS: Seven PMDD women who indicated insomnia during LP, and five controls, spent every third night throughout a complete menstrual cycle sleeping in the laboratory.

RESULTS: In PMDD and controls progesterone and core body temperature (BT(core)) were elevated during LP compared to the follicular phase (FP). Stage 2 sleep showed a significant main effect of menstrual phase and was significantly increased during mid-LP compared to early-FP in both groups. Rapid eye movement (REM) sleep for both groups was decreased during early-LP compared to early-FP. Slow wave sleep (SWS) was significantly increased, and melatonin significantly decreased, in PMDD women compared to controls.

CONCLUSIONS: PMDD women who experience insomnia during LP had decreased melatonin secretion and increased SWS compared to controls. The sleep and melatonin findings in PMDD women may be functionally linked. Results also suggest an altered homeostatic regulation of the sleep-wake cycle in PMDD, perhaps implicating melatonin in the homeostatic process of sleep-wake regulation.