PMS is premenstrual syndrome, a condition that affects menstruating women and is characterized by a variety of physical and psychological symptoms that appear from ovulation to the onset of menstrual flow, according to MedicineNet. Approximately 90 percent of women suffer from PMS symptoms at some point in their lives.
Mayo Clinic states that the symptoms of PMS recur in a predictable pattern and are at their worst during sufferers' late 20s and early 30s. Psychological or mood-related symptoms include irritability, anxiety and depression, and physical symptoms include headache, fatigue and breast tenderness. Women who find that PMS seriously disrupts their health and daily activities and who cannot manage its symptoms through lifestyle changes should seek medical assistance.