Association of predeployment gaze bias for emotion stimuli with later symptoms of PTSD and depression in soldiers deployed in Iraq.

OBJECTIVE: Biased processing of emotion stimuli is thought to confer vulnerability to psychopathology, but few longitudinal studies of this link have been conducted. The authors examined the relationship between predeployment gaze bias for emotion stimuli and later symptoms of posttraumatic stress disorder (PTSD) and depression in soldiers deployed to Iraq.

METHOD: An eye-tracking paradigm was used to assess line of gaze in 139 soldiers while they viewed a two-by-two matrix of fearful, sad, happy, and neutral facial expressions before they were deployed to Iraq. Once they were deployed, the soldiers periodically reported on their levels of war zone stress exposure and symptoms of PTSD and depression.

RESULTS: War zone stress exposure predicted higher scores on PTSD and depression symptom measures; however, eye gaze bias moderated this relationship. In soldiers with war zone stress exposure, shorter mean fixation time when viewing fearful faces predicted higher PTSD symptom scores, and greater total fixation time and longer mean fixation time for sad faces predicted higher depressive symptom scores.

CONCLUSIONS: Biased processing of emotion stimuli, as measured by gaze bias, appears to confer vulnerability to symptoms of PTSD and depression in soldiers who experience war zone stress.