Premenstrual dysphoric disorder or PMDD is a condition associated with severe emotional and physical problems that are linked closely to the menstrual cycle. Symptoms occur regularly in the second half of the cycle and end when menstruation begins or shortly thereafter. PMDD is not just a new name for premenstrual syndrome (PMS), a condition that affects as many as 75% of menstruating women. It is, however, considered to be a very severe form of PMS that affects about 5% of menstruating women. Both PMDD and PMS share symptoms in common that include depression, anxiety, tension, irritability and moodiness. What sets PMDD apart is its severity. Women with PMDD find that it has a very disruptive effect on their lives. Please read on to get more information about PMDD -- what it is, how it is diagnosed and how it is treated.