Definition of Premenstrual dysphoric disorder:

Premenstrual dysphoric disorder (PMDD) is a condition marked by severe depression, irritability, and tension before menstruation. These symptoms are more severe than those seen with premenstrual syndrome (PMS).

Causes, incidence, and risk factors:

The causes of PMS and PMDD have not been identified, although social, cultural, biological, and psychological factors all appear to be involved. Researchers estimate that PMDD affects between 3% and 8% of women in their reproductive years.

Major depression is very common with PMDD, although PMDD can occur in women who do NOT have a history of major depression.

Studies have found that women who have seasonal affective disorder (SAD), a form of depression characterized by annual episodes of depression during fall or winter that improve in the spring or summer, are likely to also have PMDD.