A Randomized Clinical Trial of Prolonged Exposure Therapy With and Without Topiramate for Comorbid PTSD and Alcohol Use Disorder

Posttraumatic stress disorder (PTSD) and alcohol use disorder (AUD) frequently co-occur. Prolonged exposure (PE) is an effective treatment for PTSD but shows smaller effects in patients with co-occurring AUD. Topiramate may help reduce alcohol use and PTSD symptoms. This double-blind, placebo-controlled outpatient clinical trial compared 12 sessions of PE plus either topiramate or placebo. One hundred U.S. veterans (mean age=45 years [SD=12], 84% men) with PTSD+AUD were randomly assigned to 16 weeks of treatment with PE+topiramate (up to 250 mg) or PE+placebo to examine effects on alcohol use and PTSD severity at posttreatment assessment and at 3- and 6-month follow-ups. Percent heavy drinking days decreased significantly for both conditions but did not differ between groups. PTSD scores were lower in the PE+topiramate group than in the PE+placebo group at posttreatment assessment, but not at follow-ups. The same patterns were observed for loss of PTSD diagnosis and meaningful PTSD symptom change. Change in secondary outcomes (depression, quality of life) did not differ between conditions. PE+topiramate was associated with a greater reduction in PTSD symptoms than PE+placebo during active treatment. The addition of topiramate led to more rapid and pronounced PTSD symptom reduction, which may be of benefit to patients. Because effects of topiramate were not maintained at longer-term follow-up, extending time on topiramate or additional strategies to prolong such effects may be useful. Topiramate did not show added benefit to PE for percent heavy drinking days or secondary outcomes.