premenstrual dysphoric disorder (PMDD), a mental health condition in women that begins 1 or 2 weeks before menstrual flow. Symptoms include depression, tension, mood swings, irritability, decreased interest, difficulty in concentrating, fatigue, changes in appetite or sleep, physical symptoms, and a sense of being overwhelmed. The condition affects 3% of menstruating women, usually between 25 and 30 years of age. Compare premenstrual syndrome.