How well a veteran adapts to postwar life is a complex problem involving psychiatric, social, biological, and environmental factors that, until 2009, tended to be studied separately. One of the first studies to examine them in context – to more fully understand who will struggle with post-combat stress, and why, and when it is most likely to begin impairing function – was the VA’s Marine Resiliency Study, a longitudinal evaluation of about 1,650 Marines conducted from 2009 to 2012 by an investigative team led by Dr. Dewleen Baker, research director for the San Diego Veterans Affairs Center of Excellence for Stress and Mental Health.
The first study to evaluate Marine resiliency, the study involved exhaustive surveys, blood and urine tests, genetics, medical record inventories, and behavioral assessments – evaluations made before, during, and after deployment – to explore the interaction of risk factors among subjects and to determine which factors contributed both to PTSD and to resilience.

One of the most startling early results, reported in early 2014, was that the strongest predictor of PTSD among subjects was blast injury: Moderate or severe brain trauma raised PTSD symptom scores by 71 percent, while mild TBI increased PTSD scores by 23 percent. Other factors, such as the heat of combat or pre-existing conditions, were influential in developing PTSD, but none were as strong a predictor as blast-caused TBI.

Baker and associates are still combing through the mountain of data yielded by the study. One of the most startling early results, reported in early 2014, was that the strongest predictor of PTSD among subjects was blast injury: Moderate or severe brain trauma raised PTSD symptom scores by 71 percent, while mild TBI increased PTSD scores by 23 percent. Other factors, such as the heat of combat or pre-existing conditions, were influential in developing PTSD, but none were as strong a predictor as blast-caused TBI.
The ability to study a group of Marines over time, as they passed from the DOD into the VA system, was enabled by a long-standing collaboration between military and VA researchers. This collaboration was expanded with last summer’s launch of the National Research Action Plan, a joint effort by the VA, DOD, and the Department of Health and Human Services to improve scientific understanding, develop effective treatments, and reduce the occurrence of mental health conditions such as TBI and PTSD, as well as the behavioral issues that often accompany them, among service members and veterans.

Mental health conditions, unlike the loss of a limb, are largely invisible, which makes them more complicated both to detect and treat among warriors. While the stigma often attached to mental health conditions has largely been eliminated along the military’s chain of command, it has tended to persist in a culture where one is often judged by his or her ability to ignore mental or emotional turmoil. But one of the most intriguing research findings in recent years has been the correlation between biomarkers – specific chemical compounds, hormones, or proteins found in the blood or cerebrospinal fluid – and the occurrence of both TBI and PTSD.
VA studies have shown that PTSD and TBI aren’t just mental disorders – they affect several molecular pathways in the brain – and in the summer of 2014, VA researchers also discovered biomarkers that correlated with suicide risk. In June, investigators at the Durham, North Carolina VAMC found a correlation between high and low levels of certain proteins in the blood serum of veterans who reported suicidal thoughts. In July, researchers at the Bronx VAMC conducted post-mortem examinations of the brain cells of people who had died by suicide, and discovered the faulty expression of a specific protein that helps in mood regulation.

While there’s still much ground to be covered before these biomarkers might be of practical use, it seems plausible, even likely, that they might someday help make “invisible” conditions such as stress or suicidal ideation as visible and treatable as other battle wounds – and that veterans will be better equipped than ever to thrive back in the world.

PTSD and suicidal ideation are complex conditions, and it remains unclear how the discovery of these biomarkers may someday translate into a clinical solution that will help to detect or treat them in patients. But to Jaeger these discoveries are among the most promising recent developments in post-deployment health research.
“Diabetes patients today have devices on the market that are commercially available, at low cost, to measure their blood sugar,” he said. “And those numbers are used by their doctors to help manage diabetes in the chronic state, not only to diagnose it, but to treat it,” he said. “So the goal with these biomarkers is to have something – a blood test or a neural imaging – that will allow a person with one of these conditions to measure a biomarker.”
Such measurements could suggest whether a treatment is working, a condition is worsening, or a patient’s mental health issues are resolving. While there’s still much ground to be covered before these biomarkers might be of practical use, it seems plausible, even likely, that they might someday help make “invisible” conditions such as stress or suicidal ideation as visible and treatable as other battle wounds – and that veterans will be better equipped than ever to thrive back in the world.

This article was first published in The Year in Veterans Affairs and Military Medicine: 2014-2015 Edition.