Premenstrual syndrome (PMS) refers to a wide range of physical or emotional symptoms that typically occur about 5 to 11 days before a woman starts her monthly menstrual cycle. The symptoms usually stop when menstruation begins, or shortly thereafter.

See also: Premenstrual dysphoric disorder (PMDD)

An exact cause of PMS has not been identified. However, it may be related to social, cultural, biological, and psychological factors.

PMS is estimated to affect up to 75% of women during their childbearing years.

It occurs more often in women:

• Between their late 20s and early 40s
• Who have at least one child
• With a family history of a major depression
• With a history of postpartum depression or an affective mood disorder

The symptoms typically get worse in the late 30s and 40s as a woman approaches the transition to menopause.

As many as 50 - 60% of women with severe PMS have an underlying psychiatric disorder (premenstrual dysphoric disorder).