04/22/2012 04:09 pm ET Updated Jun 22, 2012

Gene Screens for Soldiers

A team of scientists from UCLA and Duke have published the first study that identifies certain genes as involved in heightening the risk of post-traumatic stress disorder. Writing in the Journal of Affective Disorders, the researchers found that two genes were significantly associated with increased self-reporting of PTSD symptoms among 200 adults who experienced the Spitak, Armenia earthquake in 1988.

The statistical association was small and, as the authors point out, there are inherent flaws in self-reports, but the notion that people with a higher risk of PTSD can be identified through genetic testing raises yet another fascinating question for the new era of genomics. As more and more samples are sequenced with increasingly reliable personal histories through ever faster gene analyzers and more sophisticated algorithms, many believe these data will only become more reliable.

What are the implications for society if a serious mental illness can be avoided by deliberately excluding some people from certain sorts of situations? Should our screening mechanisms become so heavy-handed, if the technology allows it?

We might well decide that such uses of genetics should in general not be allowed. For example, the invasion of privacy could seem intolerable, especially if confidentiality cannot be guaranteed. At a more philosophical level, some will argue that it is unwise to isolate people from the inherent risks of life, that confronting sad and even painful events is part of what it is to live a full human life.

But there is one kind of human activity that is, by its very nature, both exceptionally subject to stress and largely non-voluntary in the risks it assumes: the person at the "tip of the spear" in human conflict, the warfighter. At no time in our history have we become so aware of the psychological perils associated with combat, especially in protracted duty in asymmetric conflicts amid unfamiliar cultural cues. Military planners have good reason to want to avoid inflicting personal devastation on heroic young men and women who put themselves in harm's way for the sake of the rest of us. And privacy considerations do not have the same weight in the military that they do in civilian life. Already biological samples are collected from everyone who serves in the armed forces. Along with thorough medical histories and service records they are potentially a potent source of information about the way that genes and experience interact.

Nor is psychological screening of soldiers a new idea. Early IQ tests were applied to inductees in the armed forces during World War I, and World War II saw the use of personality inventories like the Thematic Apperception Test. Put in terms of modern genetics, these psychometric measurements tell us about a person's phenotype, their genotypic behavior under certain conditions; it isn't that big a step to inquiring about the genome itself.

It's important to emphasize that the science is a long, long way from being at the point where it could reliably be applied. Many earthquake victims who don't have those genes also experienced severe and persistent stress. And those in the career military could have their prospects for important assignments and promotion severely curtailed if gene screens like this one were ever introduced. Even now a record of psychological consultation is feared in the military as a black mark on one's career prospects, which may itself be one reason that help is not sought by those most at risk.

Yet there's good reason to believe that we are on the road to more active development of behavioral genetics with at least modest predictive power. And, like so many other new technologies, those who fight our wars are among the most likely to be exposed and the least likely to have a choice.