Topiramate Monotherapy for Civilian Posttraumatic Stress Disorder: A Controlled Pilot Study

Objective: To assess the efficacy, safety, and tolerability of topiramate for the treatment of posttraumatic stress disorder (PTSD) in civilians.

Methods: This 12-week double-blind, randomized, placebo-controlled study enrolled 72 outpatients (aged 19-64 years) with a DSM-IV-TR diagnosis of non-combat-related PTSD and a score ≥ 50 on the Clinician-Administered PTSD Scale (CAPS). The primary efficacy endpoint, percent change in total CAPS score, and secondary efficacy measures were assessed by analysis of covariance. Safety assessments included monitoring of vital signs, physical examinations, clinical laboratory parameters, electrocardiograms, and adverse events (AEs). The study was conducted from October 2001 to March 2004.

Results: The intent-to-treat (ITT) population (N = 68; mean age = 35 years; 87% women; 74% White) showed greater percent reduction in total CAPS scores with topiramate versus placebo (39.5% vs 29.5%), but the difference was not statistically significant (P = .31). Similarly, higher reductions with topiramate versus placebo were seen in the CAPS subscale scores for symptoms of reexperiencing (43.6% vs 34.8%), avoidance/numbing (38.3% vs 30.6%), and hyperarousal (36.6% vs 21.4%). However, these differences were not statistically significant. Six patients in the topiramate arm had a final CAPS score < 20, whereas only 2 in the placebo arm achieved the result (P = .075). The median final topiramate daily dose was 100 mg/d (range, 25-400 mg/d), and mean ± SD treatment duration was 55 ± 32 days, showing the tolerability of the medication. In topiramate-treated patients, treatment-emergent AEs included paresthesia, headache, fatigue, and insomnia; treatment-limiting AEs included influenza-like symptoms, agitation, cognitive problems not otherwise specified, and somnolence. However, a higher rate of AE-related discontinuation was seen in the placebo group than in the treatment group (26% vs 18%).

Conclusions: In this 12-week civilian PTSD study, topiramate improved the primary and secondary outcome measures at a higher rate than did placebo, but the difference did not reach statistical significance. Further adequately powered studies may be warranted.

Trial Registration: Clinical Trials.gov identifier: NCT00208130.

Prim Care Companion CNS Disord 2023;25(5):23m03555.

Author affiliations are listed at the end of this article.