Predictors of involuntary and voluntary emotional episodic memories of virtual reality scenarios in Veterans with and without PTSD.

This study investigated predictors of involuntary and voluntary memories of stressful virtual reality scenarios. Thirty-two veterans of the two Persian Gulf Wars completed verbal memory tests and diagnostic assessments. They were randomly assigned to a Recounting (16) or a Suppression (16) condition. After immersion in the VR scenarios, the Recounting group described the scenarios and the Suppression group suppressed thoughts of the scenarios. One week later, participants completed surprise voluntary memory tests and another thought suppression task. The best predictors of voluntary memory were verbal memory ability, dissociation, and to a lesser extent, physiological arousal before and after scenarios. Dissociation and physiological stress responses selectively affected memory for neutral elements. Higher distress during scenarios impaired voluntary memory but increased the frequency of involuntary memories. Physiological stress responses promoted more frequent involuntary memories immediately after the scenarios. More frequent initial involuntary memories, tonic physiological arousal, and stronger emotional responses to dangerous events predicted difficulty inhibiting involuntary memories at follow-up. The effects of thought suppression were transient and weaker than those of other variables. The findings suggest that posttraumatic amnesia and involuntary memories of adverse events are more related to memory ability and emotional and physiological stress responses than to post-exposure suppression.