Role of Hormones in Susceptibility to Seizures in Women With Epilepsy

This study will measure and compare hormone levels in women with catamenial epilepsy (epilepsy in which seizures are more frequent during menstrual periods), women with seizures not related to their menstrual cycle, and normal control subjects. It will determine whether there are differences among the three groups in their hormone levels or in how fast the levels change. It will also examine what relationship, if any, exists between hormone changes and seizures in women with catamenial epilepsy. The hormones under study include the gonadal hormones estrone, estradiol and progesterone, and the neuroactive steroids allopregnanolone, pregnenolone, and dehydroepiandrosterone. Women who meet the following criteria may be eligible for this 3-month study: * Between 18 and 45 years of age, with catamenial epilepsy * Between 18 and 45 years of age, with seizures, but not catamenial epilepsy * Between 18 and 45 years of age, without seizures All participants will have a physical examination at the beginning of the study, at each clinic visit, and at completion or withdrawal from the study. In addition, they will undergo the following procedures: Baseline Monitoring For the first 2 months, all participants will keep a diary of their temperature and onset of menses. Women with epilepsy will also record their seizures. Electroencephalography (EEG) Healthy volunteers will have a 45-minute EEG (recording of the electrical activity of the brain) at the beginning of each menstrual cycle and each day during the menses. Women with epilepsy will have continuous EEG monitoring for 8 days, beginning 5 days before their menstrual period is expected. The continuous monitoring can be done on an outpatient basis, using a portable EEG recording device, or as an inpatient, with admission to the hospital for the 8 days of recording. Blood Sampling All participants will have a small blood sample (2 teaspoons) drawn once a day on days 10, 14, 17, 19 and 21 of their menstrual cycle and th