Do benzodiazepines reduce the effectiveness of exposure therapy for posttraumatic stress disorder?

Benzodiazepines, other anxiolytics, or sedative hypnotics are prescribed for 30%-50% of posttraumatic stress disorder (PTSD) patients. Prior data and theory suggest that these medications may inhibit response to exposure therapy, one of the most effective PTSD treatments. The present post hoc study reanalyzed results from a psychotherapy trial to assess whether benzodiazepine use was associated with reduced response to exposure therapy.

Between August 2002 and October 2005, 283 female veterans and soldiers meeting DSM-IV criteria for PTSD were randomly assigned to 10 weekly 90-minute sessions of either prolonged exposure (n = 140) or present-centered psychotherapy (n = 143). Benzodiazepine use (n = 57) or non-use (n = 226) at intake was not randomly assigned. Multilevel modeling was used to assess the effects of benzodiazepine status, psychotherapy condition, and their interaction on changes on the Clinician-Administered PTSD Scale and the PTSD Checklist during the treatment and 6-month follow-up periods.

Consistent with prior reports from these data, prolonged exposure psychotherapy produced greater reductions per week in PTSD symptoms than did present-centered psychotherapy (b = -0.48, P = .02). Patients prescribed benzodiazepines did not have weaker response to prolonged exposure, but demonstrated poorer posttreatment maintenance of gains from present-centered psychotherapy (b = -0.78, P < .001).

Prolonged exposure is a sufficiently robust treatment that patients who are taking benzodiazepines can benefit from it. It is unclear whether benzodiazepine use or other patient factors accounted for benzodiazepine recipients' poorer maintenance of gains in present-centered psychotherapy.

ClinicalTrials.gov identifier: NCT00032617.