Dec. 19, 2012 —
Science Daily/Douglas Mental Health University Institute
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 which appears in the week preceding menses, and affects about 3-8% 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% of patients frequently reporting either poor sleep quality with increased awakenings or excessive sleepiness during the symptomatic phase.
The main finding was that compared to healthy controls, 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.
Clinical implications of reduced melatonin in PMDD The prevalence of insomnia and depression are both about twice as high in women than in men, yet the reasons for this are still not fully understood. The current results highlight the importance of considering melatonin and circadian rhythms as factors leading to PMDD, with many clinical implications.