A new study has found that premenstrual dysphoric disorder (PMDD) is biologically different from major depression and a history of depression affects how women with PMDD respond to stress and pain.

PMDD is often misdiagnosed as major depression or other mood disorder. However, the new findings are important because they give physicians more reason to search for a more specific diagnosis and could possibly lead to more precise treatments, of which there are currently few good choices, said Dr. Susan Girdler, professor of psychiatry at the University of North Carolina at Chapel Hill School of Medicine who led the study.