Imagine a team of researchers in the U.S. able to remotely track a deployed soldier's reactions to combat stress in Iraq with the accuracy to determine susceptibility to post-traumatic stress disorder (PTSD) and the ability to administer quick preventative treatments. That is just one of the potential implications of Michael Telch and his team's research at the University of Texas at Austin in collaboration with 184 volunteer soldiers from Fort Hood.
Imagine a team of researchers in the U.S. able to remotely track a deployed soldier's reactions to combat stress in Iraq with the accuracy to determine susceptibility to post-traumatic stress disorder (PTSD) and the ability to administer quick preventative treatments. That is just one of the potential implications of Michael Telch and his team's research at the University of Texas at Austin in collaboration with 184 volunteer soldiers from Fort Hood.
Telch and his colleagues are the first to collect data from soldiers "in theatre" — in the combat zone, or in vivo, as he also likes to say — via monthly online stress-log surveys which require no more than 15 minutes of the service man or woman's time.
"There have been dozens of surveys [conducted] with the soldiers who are returning from Iraq and Afghanistan. Soldiers return in large numbers and they're given paper and a pencil, and from that data, we know that about 90 percent of soldiers coming back have been exposed to significant combat experience of a traumatic nature," Telch told attendees at the 2009 CASW New Horizons in Science Briefing in Austin. "Depending on the survey, about 13 to 18 percent of soldiers returning actually afford the criterion for full-blown PTSD."
This study, which only examines soldiers who have no prior combat experience, employs a unique cocktail of bio-physiological and psychological research techniques. Pre-deployment, soldiers are subjected to a battery of tests — from psychological and cognitive screenings, to neuroimaging, to genetic screening and even a carbon-dioxide stress-reaction examination in which subjects breathe in 35 percent CO2 (65 percent O2) and are tested for post-inhalation cortisol levels. While deployed, soldiers are sent e-mail reminders to complete the surveys, which monitor their stress exposure and reactions, every 30 days.
Telch explained that surveying the troops in theatre reduces error and reporting biases often associated with retrospective analyses.
"Collecting multiple assessments in vivo allows us to look at the development of these problems over time," he said. Only 4 percent of the soldiers report that talking about their combat stress-reactions is "upsetting," while 20 percent say it makes them "feel better."
When soldiers return from overseas, all of the pre-deployment tests are readministered (with the exception of genetic sampling). Since deployment, about 40 percent of the returning soldiers studied developed one or more symptoms of stress, and "about 21 percent actually have a mental disorder at the time of evaluations," Telch said.
He and his team find a significant correlation between soldiers who have been identified as having suffered mental or emotional stress in the past and those who report an elevated stress level during combat. They're also finding that the carbon-dioxide inhalation test is a satisfactory indicator of a soldier's potential anxiety based on comparisons between pre- and post-inhalation cortisol levels.
"Those who are CO2 reactive at pre-deployment are showing many more problems in theatre than those showing low- CO2 reactivity," he said. "It's a potentially useful risk indicator."
Another risk indicator the team is especially interested in are polymorphisms of the serotonin system, specifically, the presence of one or two short alleles in the serotonin transport gene, 5-HTTLPR. "5-HTTLPR status seems to predict sensitivity to emotional material and cortisol-reactivity in the CO2 challenge," explained Telch.
Of course, there is still the question of causality. Is serotonin transport gene status a by-product of an emotional disorder, such as anxiety or depression, or is it a pre-existing condition that increases one's vulnerability to such disorders? Telch and his team are poised to answer this question with future investigation utilizing their multi-disciplinary approach.
"Having a system that allows us to track stress reaction in theatre really gives us an opportunity to uncover things that we just could not do before," he said. "As we get better and better at identifying these [potential causes]," the team may be able to perform pre-deployment interventions. "Some of these risk factors really are modifiable, just like cholesterol is modifiable in heart disease," he said.
Tracy Vence is a journalist living in New York City. She received her master's degree in journalism from Northeastern University in August. She is also an intern at BioTechniques.
