American Soldiers: Study in PTSD and Eye Gaze Bias 1
American Soldiers: Study in PTSD and Eye Gaze Bias
Lesley Orr
SW 3810
3-20-2013
American Soldiers: Study in PTSD and Eye Gaze Bias 2
Every year, hundreds of our nation’s bravest soldiers come home from war zones and are
affected by Post Traumatic Stress Disorder (PTSD). Post Traumatic Stress Disorder is a
widespread disorder that is still being studied in many ways today. About 61% of Americans
have had a traumatic event in their life, but only about 8% develop Post Traumatic Stress
Disorder. While many different kinds of people are affected by PTSD, this study was done on
our American soldiers. In this study, researchers were trying to determine whether or not an eye
gaze bias is directly linked to environmental stressors and the severity of the stressors having an
effect on the onset of PTSD in soldiers. The researchers 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 (Beevers 20011). Researchers created the
hypothesis that a gaze bias to avoid fear stimuli would be associated with greater PTSD
symptoms in soldiers exposed to war zone stress and that a gaze bias toward sad stimuli would
predict greater symptoms of depression in soldiers exposed to war zone stress (Beevers 2011).
In this particular study, researchers gathered 178 U.S. Army soldiers with no prior
deployment experience, but were scheduled to deploy to Iraq. Nineteen of the participants were
dismissed because of difficulty obtaining eye tracking data and twenty were excluded because of
failure to report war zone stressors while overseas. An eye tracking paradigm was used to
measure gaze bias in the remaining 139 soldiers. This included total time, mean fixation time,
and number of fixations. Soldiers were shown a matrix of fearful, happy, sad and neutral facial
expressions prior to their deployment to Iraq. Participants were instructed to view the images on
the matrix naturally, as if they were watching television or looking at photos in an album and to
focus on whatever seemed interesting to them (Beevers 2011). Soldiers were deployed overseas
approximately three months after the predeployment assessment was done. Once the soldier was
American Soldiers: Study in PTSD and Eye Gaze Bias 3
deployed, they were required to report their levels of war zone stress exposure periodically. They
were prompted by email every 30 days to participate in a survey and were asked to complete
these assessments throughout their deployment.
The results of this study were that 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 (Beevers 2011). The results that
were found were that gaze bias is linked to vulnerability to PTSD and depressive symptoms in
soldiers who were overseas and experienced war zone stress. Another conclusion that was made
is that war zone stress exposure clearly increases vulnerability to symptoms of PTSD and
depression, although its impact varies (Beevers 2011). Soldiers with shorter fixation times on the
facial expressions that were fearful were shown with higher PTSD symptoms with increased war
zone stressors. The researchers concluded that gaze biases for emotional stimuli may help to
identify soldiers or individuals who are vulnerable to psychopathology when exposed to stressful
life experiences (Beevers 2011).
The strengths of this study was that it was carefully thought out and executed. Each part
of the study went into great detail; having soldiers identify specific stressors that they were
experiencing, along with the in depth way that the eye gaze was studied. The researchers left
very little room of error in their measurement of the eye gaze bias. They carefully tracked where
soldiers were most often focusing on, whether it was sad, happy, fearful or neutral.
American Soldiers: Study in PTSD and Eye Gaze Bias 4
Weaknesses of the study occurred when researchers decided that soldiers who focused on
the sad expressions for a longer mean fixation time developed more depressive symptoms that
PTSD symptoms when exposed to war stressors. This does not conclude that war stressors
created the depressive symptoms in the soldiers. These particular soldiers who fixated more on
the sad faces could have easily been already in a depressed stated when they took the assessment.
The research concludes that these soldiers were depressed specifically because of how the
fixated on the sad faces and their exposure to war zone stressors, which could easily be mistaken.
There was nothing to conclude that these soldiers were not already depressed before they were
even deployed.
The research article mentions limitations that this study had. One of those limitations was
that a validated but brief assessment of PTSD symptoms was used when soldiers were deployed
in Iraq. This was a 4-item scale so it was limited in the responses that soldiers could give when
taking the survey/assessment. It was a very restricted set of symptoms, so it was likely that
soldiers may not have had those exact symptoms, but answered which was closest to what they
were experiencing. Other limitations that the research mentions was the possibility of other risk
factors not measured in this particular study could have influenced the results of this study. For
example, the article mentions that neuroticism has been associated with a greater risk of PTSD.
This was not one of the disorders that was tested for in the preliminary exam, and the researchers
suggest that future work measure this risk factor and examine whether or not it contributes to a
greater risk of the onset of PTSD and depression.
Based on the results that the authors found, the conclusions that they found were
appropriate. There were few limitations to the study, along with many strengths and few
American Soldiers: Study in PTSD and Eye Gaze Bias 5
weaknesses. This study was very precise in being able to determine the relationship between eye
gaze bias and the experience of PTSD or depression in soldiers. The study was done with great
accuracy, and even with the few limitations the researchers had, the results they found were
conclusive along with very interesting. It is interesting to be able to see the relationship between
the two things that they were studying and see that this is a possible way to measure whether or
not the soldiers are vulnerable to PTSD and depression symptoms when they come back from
overseas.
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Works Cited
Beevers, C. G., Lee, H., Wells, T. T., Ellis, A. J., & Telch, M. J. (2011). Association of
predeployment gaze bias for emotion stimuli with later symptoms of PTSD and
depression in soldiers deployed in iraq. The American Journal of Psychiatry,168(7), 73541. Retrieved from
http://search.proquest.com.proxy.lib.wayne.edu/docview/893585807?accountid=14925