A closer look at premenstrual syndrome, also called premenstrual tension. The chapter explains that hormonal changes before a period can cause physical symptoms, emotional symptoms or both. While the exact cause of PMS is unknown, it describes how it may be linked to hormonal shifts after ovulation. Readers learn how common PMS is, with figures from the Office of Women's Health, and which symptoms are typical, from bloating, cramps, acne and breast tenderness to irritability and anxiety. The chapter also introduces premenstrual dysphoric disorder, a more severe form that can include depression, and encourages readers to seek help if symptoms are prolonged or worsening.