 The etiology of PMS is unknown but cyclical ovarian activity and the effect of estradiol and progesterone on serotonin and gamma-amino butyric acid are key factors. Absence of PMS before puberty, in pregnancy and after the menopause supports a role of cyclical ovarian activity in PMS etiology. PMS symptoms include psychological symptoms like mood swings, irritability, depression and feeling out of control; physical symptoms like breast tenderness, bloating and headaches; and behavioral symptoms like reduced visuospatial and cognitive ability. To diagnose PMS, symptoms should be recorded prospectively over two cycles using a symptom diary. Several symptom diaries exist but the Daily Record of Severity of Problems DRSP is reliable and simple for patients. 