 Many pharmacologic agents are dosed based on the weight of the patient, and studies are conducted to determine the appropriate doses of drugs for patients with different weights in order to find the safest and most effective dose for various weights. Valproic acid is a commonly used agent for the treatment of epilepsy, as well as migraine headaches and psychiatric disorders. This prospective study is designed to evaluate the effects of obesity on the pharmacokinetic parameters of valproic acid when compared to individuals at their healthy weight. 