Divalproex ER will be administered at an initial dose of 15mg/kg/day and will be titrated upward to a dose considered optimal by the investigator based on the subject's clinical response and adverse events, but not to exceed 30mg/kg/day. As needed (prn) use of lorazepam (0.5-2.0mg/day) will be allowed for the management of affective symptoms for the first two weeks of the study; prn lorazpam (0.5-1.0mg/day) will be allowed for the next 2 weeks; subsequently (for the final 4 weeks of the study), no lorazepam will be permitted. Zaleplon (10-20mg/day) will be allowed for management of insomnia throughout the study.