Abnormalities in the release of melatonin have been found in women with premenstrual dysphoric disorder (PMDD) and insomnia by researchers at the Douglas Mental Health University Institute in Canada.
This discovery may shed some light on why women with PMDD — also known as premenstrual syndrome — commonly experience sleep disruptions.
PMDD is a mood disorder which typically occurs the week before menstruation, and affects about 3 to 8 percent of women. PMDD sufferers can experience depression, tension, and irritability severe enough to interfere with daily activities and relationships.
Sleep difficulties are common in this disorder, with up to 70 percent of sufferers frequently reporting either poor sleep quality with several awakenings or excessive sleepiness during the symptomatic phase.
Dr. Diane B. Boivin’s team at the Douglas Institute monitored the rhythms of the hormone melatonin for 24 hours in a group of women with PMDD and a group of healthy controls.
In the study, participants underwent two 24-hour laboratory visits, once during the pre-ovulatory phase and again during the post-ovulatory phase of the menstrual cycle.
Each visit included thorough physiological monitoring under highly controlled conditions. At this time, blood samples were collected to measure levels of circulating plasma melatonin.
The main finding was that compared to healthy controls, PMDD women had significantly decreased melatonin secretion levels during the night and during the symptomatic phase.
The rates of insomnia and depression are double in women compared to men, yet the reasons for this are still not fully understood. The current findings highlight the importance of considering melatonin and circadian rhythms as factors leading to PMDD.
“Clearly understanding the mechanisms and specific pathophysiology of PMDD can help improve treatments, including both pharmacologic and non-pharmacologic approaches, for this disorder,” said lead author Dr. Ari Shechter.
By targeting the melatonin system specifically, or, more broadly, the circadian system, clinicians may be able to treat PMDD symptoms, including insomnia, more effectively.