Studies have found that between 3% and 8% of at risk (menstruating) women have PMDD. Since the disorder involves the menstrual cycle, it does not occur in children, after menopause or during pregnancy. It can, however, occur in a woman who has had a hysterectomy (surgical removal of the uterus or womb) if the ovaries have not also been removed. The usual age of onset is late teens through mid-thirties.

Remember that PMDD is a very severe form of PMS (premenstrual syndrome). PMS is far more common and may affect upwards of 75% of menstruating women. Apparently over 100 physical and emotional symptoms have been linked to the premenstrual phase of the cycle -- some of the more common are emotionality, headache, breast tenderness, bloating and weight gain. PMS symptoms may not be severe enough to qualify as PMDD, but still may be troublesome enough to require treatment.