Janice E. Daugherty, MD, Associate Professor at East Carolina University School of Medicine, wrote in a July 1998 article titled "Treatment Strategies for Premenstrual Syndrome," published in the American Family Physician online, that:

“Premenstrual syndrome (PMS) refers to a group of menstrually related disorders and symptoms that includes premenstrual dysphoric disorder (PDD) as well as affective disturbances, alterations in appetite, cognitive disturbance, fluid retention and various types of pain. The metabolic and behavioral contexts of menstrually related disorders are being carefully studied.

Premenstrual symptoms sufficient to impair daily life and relationships are estimated to affect up to 40 percent of women of reproductive age, with severe impairment occurring in approximately 5 percent. PMS may have an onset at any time during the reproductive years and, once symptoms are established, they tend to remain fairly constant until menopause.”