rTMS-augmented Written Exposure Therapy for PTSD

Overview

Post-traumatic stress disorder (PTSD) is prevalent and represents a high healthcare burden among Veterans. Repetitive transcranial magnetic stimulation (rTMS) is a brain-based therapy that may be effective for treating PTSD. The theorized mechanism of rTMS is enhancement of emotional flexibility via the dorsolateral prefrontal cortex node of the brain's cognitive control network. Given this mechanism of action, adding rTMS to an evidence-based psychotherapy (EBP) for PTSD may enhance treatment effects. Written exposure therapy (WET) is a brief EBP for PTSD found to reduce attrition compared to lengthier first line treatments. In this study, the investigators will determine if active rTMS added to WET compared with sham rTMS added to WET results in improved PTSD outcomes. The investigators will also determine if emotional flexibility is a mechanism of symptom improvement. This work will improve upon PTSD intervention and inform the mechanism of treatment effectiveness for Veterans suffering from PTSD.

The overarching goal of this CDA-2 proposal is to use repetitive transcranial magnetic stimulation (rTMS) to augment effectiveness of written exposure therapy (WET), a narrative-based trauma exposure paradigm, in treating posttraumatic stress disorder (PTSD) and emotion dysregulation in Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF) Veterans. As a clinical neuropsychologist with expertise in emotion regulation, Dr. Lantrip's long-term goal is to improve upon and develop effective interventions for trauma-related illness in Veterans by identifying and targeting behavioral and neural mechanisms. OEF/OIF Veterans have experienced increased length and number of deployments, contributing to diagnosis of PTSD. rTMS is a brain-based therapy involving application of a repetitive, brief magnetic pulse to the scalp through an electromagnetic coil. rTMS applied to the dorsolateral prefrontal cortex (DLPFC) has efficacy in patients with treatment-resistant depression, and recent work has shown efficacy for treating PTSD. Standard rTMS treatments are stand-alone, though the unique properties of rTMS may make it more effective when added to a psychotherapy such as an evidence-based psychotherapy (EBP) for PTSD. rTMS is theorized to act on the DLPFC node of the brain's cognitive control network (CCN) to improve emotion regulatory processes and facilitate reduction in affective symptoms. In support of this theory, studies have found that improvements in affective flexibility, upregulation of positive affect, and downregulation of attention to negative stimuli occur in task-based paradigms immediately following stimulation of the DLPFC with rTMS in a single-session. In addition, recent research has found that rTMS prior to cognitive processing therapy (CPT) in Veterans with PTSD is effective at improving PTSD outcomes compared to sham rTMS plus CPT, possibly through the regulatory mechanism of the CCN. Given these promising findings, further study into optimizing rTMS-augmented EBPs for PTSD is warranted. There are limitations to both rTMS and first line EBPs for PTSD. One problem is high numbers of sessions needed for effective treatment (i.e. 20 sessions of rTMS and 12-18 sessions of EBPs) contributing to high attrition rates. A large multi-site study of VA patients in PTSD clinic found that just 2% of a sample of 1924 Veterans who had at least one session of EBP received an "adequate dose" of at least 8 sessions.12 A potential optimization for rTMS-augmented EBPs would be to reduce session number to improve retention. WET is a novel EBP for PTSD that is non-inferior to CPT in as few as 5 sessions. Using rTMS to augment WET in Veterans with PTSD is a crucial step in this line of inquiry. This double-blind, Phase II randomized controlled trial will examine whether rTMS added to WET results in superior outcomes compared to sham rTMS added to WET (N=98 with women and men equally represented). The investigators will randomize 49 OEF/OIF Veterans with PTSD to undergo an active rTMS/WET treatment protocol versus 49 OEF/OIF Veterans given a sham rTMS/WET treatment. Specific Aim 1: To compare PTSD outcomes of those who experience active rTMS/WET versus sham rTMS/WET. Hypothesis 1: Active rTMS added to WET will contribute to greater PTSD symptom reduction compared to sham rTMS added to WET in Veterans with PTSD. Specific Aim 2a: If there is a treatment effect in Aim 1, determine if emotional flexibility mediates the rTMS/WET-PTSD relation. Aim 2b (exploratory): Determine if emotional flexibility has a unique mediating effect over cognitive flexibility. Hypothesis 2a: Significant reduction in PTSD symptoms will be partially mediated by emotional flexibility. Hypothesis 2b: Significant reduction in PTSD symptoms will be partially mediated by cognitive flexibility, but to a lesser extent than emotional flexibility. This CDA-2 extends Dr. Lantrip's research integrating emotion regulation and neurostimulation to understand and improve upon treatment of PTSD in Veterans. The CDA-2 will provide her with specialized training in WET, a unique exposure-based therapy for the treatment of trauma, as well as clinical trials for PTSD, and neurostimulation. The mentoring team integrates expertise in the proposed areas of study and extensive experience mentoring early career investigators. Project findings will inform a future VA Merit proposal, which will focus on individual differences and mechanisms contributing to PTSD symptom improvement in TMS-augmented behavioral therapy. This study has the potential to inform and improve upon existing treatments for PTSD. Together, Dr. Lantrip's work aligns with VA's priorities, CR\&D's mission, and with the goal to provide the highest quality of care for Veterans.