Background: Few effective pharmacotherapeutic strategies have been established for the treatment of symptoms associated with posttraumatic stress disorder (PTSD). Preliminary evidence supports the efficacy of serotonergic agents and anticonvulsants, such as divalproex sodium, for the treatment of PTSD symptoms, particularly in military populations.Objective: The aim of this study was to obtain pilot data on the use of divalproex sodium for the treatment of PTSD among adult civilian outpatients with a history of childhood physical and/or sexual abuse.Methods: Outpatients with a primary psychiatric diagnosis of PTSD received open-label, flexibly dosed divalproex sodium as adjuvant therapy or monotherapy for 8 weeks. Overall and subcluster PTSD features, as well as affective symptoms and clinical global improvement, were monitored using standardized assessment scales.Results: A total of 7 patients (5 women, 2 men; mean age, 44.1 years [range, 29-57 years]) were enrolled. At a mean (SD) peak dosage of 1500 (661) mg/d, significant improvement occurred in overall PTSD symptom severity (P Ͻ 0.02) and in the diagnostic subclusters of hyperarousal and avoidance (P Ͻ 0.02 for both). Depressive symptoms also were significantly improved from baseline (P Ͻ 0.02). Divalproex sodium was well tolerated, except in 1 patient who prematurely discontinued treatment due to cognitive adverse events.Conclusions: These provisional findings support the possible utility of divalproex sodium therapy for adult outpatients with PTSD related to physical and/ or sexual abuse during childhood. Controlled trials with larger sample sizes powered to show safety and efficacy are needed to substantiate these initial