A new study by Douglas Mental Health University Institute researchers shows altered body rhythms of the hormone melatonin in premenstrual dysphoric disorder (PMDD) women with insomnia. This finding may help explain some of the sleep disruptions experienced by women with PMDD, also known as premenstrual syndrome.
PMDD is a mood disorder that appears in the week preceding menses and affects about 3-8 percent of women. PMDD sufferers can experience depression, tension, and irritability of sufficient intensity to interfere with daily activities and relationships. Disturbed sleep is also a common symptom of the disorder, with up to 70 percent of patients frequently reporting either poor sleep quality with increased awakenings or excessive sleepiness during the symptomatic phase.
“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.
The study, published in the December 2012 issue of the journal PLOS ONE, investigated how rhythms of the hormone melatonin vary across the 24-hour day in a group of women with PMDD and a group of healthy controls. Participants underwent two 24-hour laboratory visits, once during the pre-ovulatory follicular phase and again during the post-ovulatory luteal phase of the menstrual cycle. Each visit consisted of intensive physiological monitoring under highly controlled time-isolation conditions. During this time, blood samples were collected to determine circulating plasma melatonin levels.
Results show that PMDD women had significantly decreased melatonin secretion levels during the night-time hours. PMDD women also had a further reduction of melatonin levels during their symptomatic luteal phase compared to the asymptomatic follicular phase.
In addition to insomnia, some of the sleep disorders that are most likely to affect women include sleep apnea, snoring, restless legs syndrome (RLS), and parasomnias such as sleep-related eating disorder (SRED) and nightmare disorder.
