Differences Between PMS and PMDD
PMS and PMDD differ in degree. Not only are mood symptoms more severe, researchers have found further differences between PMDD sufferers and other women, both with and without PMS.
For one, women with PMDD have greater pain sensitivity than women with PMS. In a 2000 study of fifty-four women, twenty-seven with PMS and twenty-seven with PMDD, psychiatric experts at the University of North Carolina found that women with PMDD had lower pain threshold than women with PMS when their blood flow their arms was restricted using blood pressure cuffs. PMDD sufferers also had shorter times of pain tolerance than the women with PMS. One reason may be that the PMDD sufferers had low levels of beta-endorphins in their blood. These endorphins are natural painkillers, and PMDD sufferers had levels that were 30 percent lower than women with PMS.
Fact
PMDD, which tends to develop in women in their late twenties, can affect between 1,400 and 2,800 days in a woman’s lifetime, or four to eight years’ worth of symptomatic days.
Women with PMDD are also much likelier to have been sexually abused than other women. Between 50 and 60 percent of women with PMDD have histories of physical or sexual abuse, while experts estimate the rates for the general population are much lower at 20 to 25 percent. PMDD sufferers may also have dysregulated stress response systems. A 1998 study at the University of North Carolina tested the stress responses of twelve women with PMDD and twelve healthy women and found that women with PMDD had chronic stress in their daily lives. Blood tests showed abnormally elevated levels of the stress hormone norepinephrine and abnormally low levels of cortisol. The high levels of norepinephrine remained constant, regardless of the day of the women's cycles.
