New research makes the next leap toward pinning part of the devastating disorder to heredity. (Photo: Getty Images)

Imagine a world in which you would be able to say, “Okay, 10 people want to go to war. Maybe we should only send these five.”

That’s the sort of life-changing idea that researchers are racing toward as they close in on understanding the genetic component of post-traumatic stress disorder (PTSD).

“Among 10 people that are deploying to war, we could understand who is more, and who is less vulnerable to PTSD, and can develop preventions accordingly,” says Caroline Nievergelt, PhD, of the University of California, San Diego, School of Medicine. And that’s just the beginning.

Throughout their lifetimes, about 61 percent of men and 51 percent of women experience at least one traumatic experience. About 8 percent of people experience post-traumatic stress disorder (PTSD), with about 5 million Americans suffering from it during any year. War veterans, law enforcement officials, firefighters and EMT workers are particularly vulnerable to PTSD — and women are twice as likely to experience it than men.

PTSD has been a consistent headline in the media due to its link with veteran suicides. George Washington University’s Face The Facts project estimates that 1 in 5 veterans of the Iraq and Afghanistan wars have been diagnosed with PTSD — and veterans account for 20 percent of suicides in the U.S, claiming the lives of about 22 vets every day.

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But doctors and researchers hope that soon we will be able to use the science of genetics to make these numbers much lower — starting today.

In a novel study published Tuesday from the Veterans Affairs San Diego Healthcare System and University of California, San Diego School of Medicine, researchers analyzed blood samples from Marines before and after deployment into combat zones. Past studies have focused solely on veterans diagnosed with PTSD after returning from combat — but this previous research has demonstrated that genetics are heavily involved in whether or not someone gets PTSD, and could account for over 40 percent of one’s risk, says Nievergelt.

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“The controls in the study all had similar amounts of combat exposure and negative stress,” Nievergelt, a co-author of the study, tells Yahoo Health. “That’s a very unique setting because you can better investigate risk and resilience when all study participants experience similar levels of trauma.”

This study found “both similar and different biomarker signatures before developing PTSD and after,” says Nievergelt. Most of the studies that have been performed regarding PTSD have looked at people with the disorder and compared them with people without it — comparing apples with oranges instead of apples with apples, and following them over time, as this study does.

Interestingly, the genes involved in innate immune response — the body’s first line of defense against pathogens — and interferon signaling, were also associated with PTSD. Interferons are proteins released in response to pathogens in our bodies, and in this study, were also shown to partake in the pathology PTSD.



That means that something may be stimulating this interferon response before PTSD ever develops. Researchers say a number of factors could be to blame, ranging from increased anticipatory stress before deployment to a more complex scenario where an individual may have a higher viral load. That’s a question for future studies.

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The most powerful implications of this work could be that doctors could potentially ID people who may be susceptible to PTSD before they are ever exposed to a traumatic event, says Nievergelt. But while these findings are novel, research still has a long way to go.

The hope is that someday you may not have to rely on asking someone how they feel to diagnose a specific disorder, you could also look at their blood, Nievergelt says. “There would have to be a very specific test to differentiate between PTSD and other psychological or physiological distress, of course, but in theory, it could work. This study is just a first step.”

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