While Post-traumatic stress disorder (PTSD) has become highly stigmatized as a mental health condition within the armed forces, where soldiers often return home from battle with the debilitating condition, it appears that not only may some soldiers be genetically predisposed to it-some may have immunological reactions that even make it worse. In a new study published this week in the journal Molecular Psychiatry, a team of researchers with the University of Southampton (UK) and University of California, San Diego have uncovered the genetic markers that could theoretically allow them to identify soldiers or patients that may be most at risk, even before they're deployed at all.
Linking their study to the most noted occurrences of PTSD being after war-like situations of violence, the researchers investigated the blood of 188 US Marines before and after they were deployed into conflict zones. While past studies aimed to uncover genetic markers for PTSD by investigating varying gene expression in sufferers versus non-sufferers, the new study took a more encompassing approach that allowed them to look at the entire genome-not just what was happening at the level of expression.
"By comparing US Marines who develop PTSD symptoms to those who do not, we can measure differences in genes, but also take into consideration the dynamic relationships between and among them, their connectivity" lead author of the study with the University of Southampton, Michael S. Breen says. "Because PTSD is thought to be such a complex disorder, measuring these dynamic relationships is crucial to better understanding the PTSD pathology."
Using whole transcriptome RNA sequencing to analyze the blood samples, the team of researchers found multiple genes that were linked to PTSD. But more than that, the researchers also found that these same genes are responsible for the regulation of the innate immune system and signaling within the body. But many are left wondering: what is triggering this signaling pathway?
"The answer could be any number of factors" coauthor of the study with the University of California, San Diego, Dr. Dewleen G. Baker says. "Ranging from a simple explanation of increased anticipatory stress prior to deployment, or even more complex scenarios where individuals may have a higher viral load. It's a question for future studies."
While the researchers will continue to investigate the causation of these genes being activated by PTSD, their study points towards some sufferers of PTSD having uncontrollable immunological responses, much like others have allergies. This discovery may in fact help destigmatize the condition. In addition, the researchers explain that adopting the approach could one day lead to the creation of a blood panel of biomarkers that could help them identify which patients may be more genetically predisposed to PTSD, and eventually lead to a way of mitigating the condition.
