Emotional dysfunction is evident in posttraumatic stress disorder (PTSD), yet it is unclear what aspects of the disorder most directly relate to aberrant emotional responding. Also, the frequent co-occurrence of blast-related mild traumatic brain injuries (mTBIs) among recently deployed U.S. military personnel complicates efforts to understand the basis for emotional disruption. We studied a cross-sectional sample (enriched for PTSD and mTBI) of 123 U.S. veterans of wars in Iraq and Afghanistan. We measured subjective affective evaluations and peripheral psychophysiological responses to images with pleasant, neutral, unpleasant, and combat-related aversive content. When compared with other postdeployment participants, those who had combat-related PTSD rated pleasant image content as less positive (η2 p =.04) and less arousing (η2 p =.06), and exhibited heightened physiological responsivity to combat image content (η2 p =.07). Symptoms of PTSD were associated with elevated skin conductance responses (β =.28), reduced heart rate deceleration (β =.44 to.47), and increased corrugator facial muscle electromyography (β =.47). No effects for blast-related mTBI were observed across any affective modulation measures. These findings point to a greater impact of PTSD symptomatology than blast-related mTBI on emotional functioning and highlight the utility of dimensional assessments of psychopathology for understanding the effects of combat-stress conditions on adjustment to civilian life.
Bibliographical noteFunding Information:
This work was supported by the National Science Foundation Graduate Research Fellowship Program (CAM; 00039202); the Congressionally Directed Medical Research Program (SRS); and the Department of Defense (SRS; PT074550). The funding sources were not involved in the choice of topics, study design, data analysis or interpretation, or preparation/submission of the manuscript. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation, the Department of Defense, the Department of Veterans Affairs, or the Department of Health and Human Services. The authors wish to thank Kevin Roberts and Russell Bacon for assistance with selection of the combat images. The authors are indebted to the U.S. military veteran participants whose involvement made this work possible.