Written exposure therapy augmented with transcranial direct current stimulation for posttraumatic stress disorder: A pilot randomized clinical trial

Written exposure therapy (WET) is an evidence-based, trauma-focused psychotherapy for posttraumatic stress disorder (PTSD) that has been tested with several trauma-exposed samples. Although many individuals who receive WET and other trauma-focused psychotherapies experience a significant reduction in PTSD symptoms, there remains room for improvement given that a meaningful proportion of individuals continue to meet the diagnostic criteria following treatment. Adjunctive interventions that can be easily combined with trauma-focused psychotherapies for PTSD may improve treatment outcomes. Transcranial direct current stimulation (tDCS) is a noninvasive neurostimulation intervention that has demonstrated preliminary evidence of reducing PTSD symptoms. In this study, we combined WET with tDCS to treat PTSD in a pilot randomized clinical trial. Participants (N = 25) received five WET sessions and were randomized to active or sham tDCS targeting the dorsolateral prefrontal cortex. Results showed no statistically significant group differences in PTSD symptom reductions at 1-month follow-up, as assessed using the Clinician-Administered PTSD Scale for DSM-5 or PTSD Checklist for DSM-5 (PCL-5), ps = .573-.619, and both treatment groups demonstrated significant PTSD improvements, ps < .001, at the final assessment point. However, there was a significant two-way interaction for the PCL-5, p = .010. Deconstruction of this interaction showed that WET with tDCS had an accelerated effect, with larger PTSD symptom reductions occurring earlier in treatment relative to WET with sham tDCS. The findings highlight the potential of tDCS to accelerate PTSD outcomes when combined with WET and support conducting larger randomized clinical trials.