Efficacy and safety of topiramate monotherapy in civilian posttraumatic stress disorder: a randomized, double-blind, placebo-controlled study.

OBJECTIVE This double-blind, placebo-controlled trial assessed efficacy and safety of topiramate monotherapy in civilian posttraumatic stress disorder (PTSD). METHOD Outpatients (18-64 years) with DSM-IV non-combat-related PTSD and Clinician-Administered PTSD Scale (CAPS) scores >or= 50 were eligible. Topiramate was started at 25 mg/day and titrated by 25-50 mg/week to 400 mg/day or maximum tolerated dose. Data were collected between April 26, 2002, and February 4, 2004. Primary efficacy, change in total CAPS score, and secondary efficacy measures were assessed by analysis of covariance in the intent-to-treat (ITT) population with last observation carried forward. RESULTS The ITT population comprised 38 patients with mean +/- SD baseline total CAPS scores of 88.3 +/- 13.8 (topiramate, N = 19) and 91.1 +/- 13.7 (placebo, N = 19). Although a decrease in total CAPS score was noted (topiramate, -52.7; placebo, -42.0), this difference was not statistically significant (p = .232). Topiramate-treated patients exhibited significant reductions in reexperiencing symptoms (CAPS cluster B: topiramate, 74.9%; placebo, 50.2%; p = .038) and Treatment Outcome PTSD scale (topiramate, 68.0%; placebo, 41.6%; p = .025). Reductions approaching statistical significance, based on a nominal p value, were noted in mean total Clinical Global Impressions-Improvement Scale scores (topiramate, 1.9 +/- 1.2; placebo, 2.6 +/- 1.1; p = .055). CONCLUSION These preliminary results suggest that further, adequately powered studies of topiramate for the treatment of civilian PTSD are warranted.