This study will last 6 weeks. Participants will be randomly assigned to receive treatment with Depakote or placebo. Medication will be given in a single evening dose if tolerated; otherwise, medication will be given twice per day. Participants will be assigned to a fixed-flexible dosing schedule and dosages will increase based on weight. All participants will attend weekly psychotherapy and family counseling sessions throughout the study. Participants who are substance abusers will also receive substance abuse counseling. Weekly study visits will include a physical exam, blood collection, and drug tests. Teachers and guidance counselors will be contacted to assess the participant's behavior from week to week. Some participants will complete a follow-up study, in which they will take part in phone interviews.