“More accurate means of predicting or screening for PTSD could help to overcome the disorder by identifying individuals at high risk of developing PTSD and providing them with early intervention or prevention strategies,” said study investigator Stacy-Ann Miller, MS.
She also noted that the biomarkers could be used to monitor treatment for PTSD, identify subtypes of PTSD, and lead to a new understanding of the mechanisms underlying PTSD.
The findings were presented at Discover BMB, the annual meeting of the American Society for Biochemistry and Molecular Biology.
Toward better clinical assessment
The findings originated from research conducted by the Department of Defense–initiated PTSD Systems Biology Consortium. The consortium’s goals include developing a reproducible panel of blood-based biomarkers with high sensitivity and specificity for PTSD diagnosis and is made up of about 45 researchers, led by Marti Jett, PhD, Charles Marmar, MD, and Francis J. Doyle III, PhD.
The researchers analyzed blood samples from 1,000 active-duty Army personnel from the 101st Airborne at Fort Campbell, Ky. Participants were assessed before and after deployment to Afghanistan in February 2014 and are referred to as the Fort Campbell Cohort (FCC). Participants’ age ranged from 25 to 30 and approximately 6% were female.
Investigators collected blood samples from the service members and looked for four biomarkers: glycolytic ratio, arginine, serotonin, and glutamate. The team then divided the participants into four groups – those with PTSD (PTSD Checklist score above 30), those who were subthreshold for PTSD (PTSD Checklist score 15-30), those who had high resilience, and those who had low levels of resilience.
The resilience groups were determined based on answers to the Generalized Anxiety Disorder Questionnaire, Patient Health Questionnaire, Pittsburgh Sleep Quality Index, Intensive Combat Exposure (DRRI-D), the number of deployments, whether they had moderate or severe traumatic brain injury, and scores on the Alcohol Use Disorders Identification Test.
Those who scored in the high range at current or prior time points or who were PTSD/subthreshold at prior time points were placed in the low resilience group.
Ms. Miller noted that those in the PTSD group had more severe symptoms than those in the PTSD subthreshold group based on the longitudinal clinical assessment at 3-6 months, 5 years, and longer post deployment. The low resilience group had a much higher rate of PTSD post deployment than the high resilience group.
Investigators found participants with PTSD or subthreshold PTSD had significantly higher glycolic ratios and lower arginine than those with high resilience. They also found that those with PTSD had significantly lower serotonin and higher glutamate levels versus those with high resilience. These associations were independent of factors such as sex, age, body mass index, smoking, and caffeine consumption.
Ms. Miller said that the study results require further validation by the consortium’s labs and third-party labs.
“We are also interested in determining the most appropriate time to screen soldiers for PTSD, as it has been noted that the time period where we see the most psychological issues is around 2-3 months post return from deployment and when the soldier is preparing for their next assignment, perhaps a next deployment,” she said.
She added that previous studies have identified several promising biomarkers of PTSD. “However, like much of the research data, the study sample was comprised mainly of combat-exposed males. With more women serving on the front lines, the military faces new challenges in how combat affects females in the military,” including sex-specific biomarkers that will improve clinical assessment for female soldiers.
Eventually, the team would also like to be able to apply their research to the civilian population experiencing PTSD.
“Our research is anticipated to be useful in helping the medical provider select appropriate therapeutic interventions,” Ms. Miller said.
A version of this article first appeared on Medscape.com.