<qa>  What is the first day of the study?On the first day of the study, participants will have a baseline TMS and will be randomly assigned to take one of two antiepileptic drugs: group A will take the carbamazepine; group B will take lamotrigine. If they wish, participants may be admitted to the NIH Clinical Center for the first 5 days of drug administration while the proper dosage is being determined. They will then be discharged and continue taking the drug for a total of 36 days. During this time, they will have daily blood tests and TMS from days 2 through 5, and again on days 12 and 36. Group A will have additional blood sampling and TMS on days 37, 39, 44, and 53; Group B will have blood tests and TMS on days 38, 40, 45, and 53. 