A new study addresses premenstrual dysphoric disorder (PMDD), a severe mood disorder which affects five to seven percent of all women of reproductive age in the United States.
Unfortunately, the disorder is often misdiagnosed as major depression or other mood disorders.
In the study, PMDD is determined to be a biologically different form of premenstrual syndrome. Women with PMDD who have experienced depression may make up a subset.
The findings are important because they give physicians more reason to search for a more specific diagnosis and could possibly lead to more precise treatments. There currently are few good choices, said Susan Girdler, Ph.D., professor of psychiatry at the University of North Carolina at Chapel Hill School of Medicine. Girdler led the study.
“PMDD is not garden-variety premenstrual symptoms. PMDD causes severe impairment in quality of life, equivalent to post-traumatic stress disorder, major depressive disorder and panic disorder, that continually cycles on a monthly basis. Some women spend half their lives suffering from this disorder,” said Girdler.
In a study published in the journal Biological Psychology, Girdler and her colleagues measured biological responses to stress and pain.
Previous studies demonstrated that women with chronic major depression have a heightened biological response to stress and release more stress hormones, such as cortisol.
Girdler and her group previously have shown that women with PMDD respond conversely, with blunted stress responses.
The current study is the first known head-to-head comparison of the two groups and confirmed earlier findings.
“We found the greatest weight of evidence that PMDD and major depression are really two distinct entities in terms of biological response to stress and with respect to pain sensitivity and pain mechanisms,” Girdler said.
But more important, Girdler said, was the finding that women with PMDD who also had experienced depression in the past looked different from PMDD women who had never been depressed. Only the PMDD women with prior depression had lower cortisol and greater sensitivity to pain compared to non-PMDD women with prior depression. These differences between PMDD and non-PMDD women were not seen in women who had no depression history.
“So while the study shows that PMDD is biologically different from major depression, a history of depression may have special relevance for women with PMDD with respect to stress hormones and pain response,” Girdler said.
Current treatments for PMDD are effective in only about half of women. But, Girdler says, gathering more biological clues about PMDD could expand the treatment options.
Source: University of North Carolina