Changes in Physiological Reactivity in Response to the Trauma Memory During Prolonged Exposure and Virtual Reality Exposure Therapy for Posttraumatic Stress Disorder

Objective: A key symptom of posttraumatic stress disorder (PTSD) is hyperreactivity to trauma-relevant stimuli. Though physiological arousal is reliably elevated in PTSD, the question remains whether this arousal responds to treatment. Virtual reality (VR) has been posited to increase emotional engagement during prolonged exposure therapy (PE) for PTSD by augmenting imaginal exposures with trauma-relevant sensory information. However, the comparative effects of VR exposure therapy (VRE) have received limited empirical inquiry. Method: Ninety active-duty soldiers with combat-related PTSD participating in a randomized-controlled trial to receive PE, VRE, or a waitlist-control (WL) condition had their physiological reactivity, indexed by galvanic skin response (GSR), to their trauma memories assessed at pre-, mid-, and posttreatment. Results: Although both VRE and PE conditions showed reduced GSR reactivity to trauma memories from pre- to posttreatment, only the VRE group differed significantly from WL. Across the sample, reductions in GSR were significantly correlated with reductions in self-reported PTSD and anxiety symptoms. Conclusions: This was the first study comparing effects of VRE and PE on psychophysiological variables. Given previous research finding limited differences between VRE and PE in PTSD symptom reduction, these findings lend support to the rationale for including VR in exposure therapy protocols while raising important questions about the potential benefits of VRE.