Patient description: A 42-year-old healthy woman came to the clinic to have her flu shot in early October. She works in a rehab center and has no underlying disease. It's her first time getting the vaccine this year. She is married for 5 years and uses barrier methods of contraception. Her menstrual cycle is irregular. She does not smoke. She is not on any medications. She exercises regularly for 30 minutes a day at least 5 days a week. She has no history of allergies to any food or drugs. Her past surgical history is significant for tonsillectomy and she is otherwise healthy.

Clinical trial eligibility criteria: eligible ages (years): 18.0-50.0,  Premenstrual Dysphoric Disorder PMDD diagnostic and severity 1. Women with PMDD according to DSM-IV-TR At screening by history At the end of the Qualification Phase by review of symptom records. 2. The first 2 consecutive or 2 out of 3 consecutive qualification cycles must fulfill the following For women who were not on any medications for the PMDD symptoms Late luteal phase (7 days which the last six days before menses through day one) daily average of > or equal 3.5 for at least 4 of 7 of these days on any 5 distinct items with no overlap on Daily Record of Severity of Problems (DRSP) Scale, at least one item must represent a non-physical symptom. Entries in the diary must be present for at least three of these days for the item to be used as an criterion for that month Follicular phase (days 8-12 after first day of menses) daily average less than or equal 2.5 on DRSP scale for non-physical symptoms only. The average will be calculated for days 8-12 of the cycle, day 1 being the first day of menstrual bleeding. Entries in the diary must be present for at least three of these days for the item to be used as an criterion for that month Late luteal phase (6 days before menses through day 1) daily average at least twice as high as follicular phase daily average for five distinct items Functional impairment questions for late luteal phase require more than or equal to 4 score on at least one item for at least 2 or more days For women who were on anti-depressants or oral contraceptive for at least 2 months Late luteal phase daily average of 2.5 or more for at least 4 of 7 of these days on any 5 distinct items with no overlap on DRSP-scale, at least one item must represent a non-physical symptom. Entries in the diary must be present for at least three of these days for the item to be used as an criterion for that month  Women, who are pregnant, gave birth within the last 8 months, breast-feeding or intending to become pregnant within 6 months. 2. Contraindication or hypersensitivity to levetiracetam. 3. Ongoing psychotherapy, which has begun <3months prior to the study visit. 4. Participation in another clinical trial within the last 3 months prior to the screening visit. 5. Known hypersensitivity to Levetiracetam 6. Any disease or condition that can compromise the function of body systems and which could result in altered absorption, excessive accumulation, impaired metabolism, or altered excretion of the study medication. 7. Severe systemic disease that might interfere with the conduct of the study or the interpretation of the results. 8. Uncontrolled thyroid problems. 9. Active use of substances, excluding caffeine and nicotine, will not be permitted during the study