April 20, 2009 — Poor physical or mental health prior to combat exposure may predispose military personnel to an increased risk for new-onset posttraumatic stress disorder (PTSD) after deployment, new research suggests.
A large prospective study that included 5410 veterans showed deployed military personnel with the lowest baseline measures of physical or mental health had 2 to 3 times the risk of having PTSD symptoms or diagnosis.
"To our knowledge, this is the first study to prospectively investigate diminished physical and mental health in relation to new-onset symptoms or diagnosis of PTSD. This study suggests diminished mental or physical health status before combat deployment is strongly associated with an increased risk of PTSD after deployment," lead author Cynthia LeardMann, told Medscape Psychiatry.
The investigators also note that the findings provide "strong evidence that physical and mental health is essential for prevention of a large portion of PTSD after combat."
The study is published online April 16 in BMJ.
Baseline Mental Health Strongest Predictor
PTSD has been linked to diminished health status and quality of life. However, most previous studies have been based on cross-sectional or retrospective data, and therefore, the authors note, this has made it difficult to determine the effects of substandard physical or mental health on new-onset or persistent symptoms of PTSD.
To investigate this question, investigators used data from the Millennium Cohort Study, a 21-year longitudinal study designed to determine the long-term effects of military service on health. It includes an invited cohort randomly selected from all US military personnel serving in October 2000.
Using the medical outcomes study SF-36 health survey for veterans, mental and physical health was assessed at baseline between July 2001 and 2003. Follow-up data were obtained between 2004 and 2006, after study subjects had their first combat deployment in Iraq and Afghanistan.
Of 5410 eligible participants (deployed between baseline and follow-up and reporting combat exposures), 397 (7.3%) had new-onset symptoms or diagnosis of PTSD at follow-up. After adjustment for all other variables, the researchers found military service members who were below the 15th percentile for self-reported baseline mental health accounted for 35% of the incidence of PTSD after combat deployment.
Furthermore, the authors that reported 58% of those with new-onset PTSD fell below the 15th percentile for mental or physical health at baseline.
Overall, investigators found a 3-fold increase in new-onset symptoms or diagnosis of PTSD among those below the 15th percentile of mental health and a 2-fold increase of new-onset PTSD symptoms or diagnosis of PTSD among those below the 15th percentile of physical health.
At-Risk Population Identified
According to Ms. LeardMann, previous research indicates that psychological processes during traumatic or stressful experience may be shaped by a multitude of integrated factors, including perception, interpretation, and evaluation of the traumatic event, as well as coping strategies used and other personal and social factors.
"Therefore," she said, "individuals with diminished mental health prior to a traumatic experience might be more likely to react poorly to the stressful event, including having a negative response and dissociative experience."
She added that having diminished mental health prior to the event may not only affect the reaction while the trauma is occurring but possibly the coping strategies used after the event.
"We have identified an at-risk population whose functional health seems to predict vulnerability to PTSD after combat deployment. In theory, such a population could be targeted for PTSD prevention programs, early intervention after exposure to stress, or even protection from stressful exposures, when possible," the authors write.
The study was funded by the US Department of Defense. The authors report no disclosures.
BMJ. Published online April 17, 2009. Abstract
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