Study links weak immune systems, PTSD - Navy News | News from Afghanistan & Iraq - Navy Times

Study links weak immune systems, PTSD

A study shows that there may be a reason that those with chronic post-traumatic stress disorder deal with more physical health issues as they age: Their immune system has been compromised.

The study is yet more evidence to support the idea that people with PTSD go through chemical changes after a psychological injury.

Lead author Monica Uddin, a researcher with the Department of Epidemiology at the University of Michigan School of Public Health, and her colleagues began with the theory that the increase in physical health issues — such as heart disease — in those with PTSD may come from immune system problems.

To that end, they used blood samples from 100 people in the Detroit Neighborhood Health Study. Of those, 23 had been diagnosed with chronic PTSD while 77 had not, though many had been diagnosed with other mental health issues, such as depression.

By looking at genes in those blood samples, they found that the people with PTSD had three areas where genes had been methylated — turned on, essentially — at higher levels than those without PTSD. One of those areas was hearing.

“Among the genes uniquely methylated in the PTSD-affected group, it is striking that the second-most enriched cluster — sensory perception of sound — directly reflects one of the three major symptom clusters that define the disorder,” Uddin wrote. That cluster is exaggerated startle response.

But the researchers found that this response tends to develop over time, which raised questions about whether the chemical changes are immediate, or if they also develop over time. Or, do the differences in genes exist before people develop PTSD?

The researchers also found that the people with PTSD were less likely to “turn on” immune-system genes.

This “suggests a biologic model of PTSD etiology in which an externally experienced traumatic event induces downstream alterations in immune function by reducing methylation levels of immune-related genes,” the study stated.

The researchers said that may be because a person’s most necessary systems respond to danger, while everything else slows. Usually, when the danger is gone, everything goes back to normal. But some people stay at some level of that hyper-alert state.

In addition to the lack of activation of immune system genes, the researchers looked at levels of antibodies to a normally latent herpes virus — cytomegalovirus — that usually remains symptom-less. But in those with a weakened immune system, it can cause anything from flu-like symptoms to visual impairment, inflammation of the brain, pneumonia, diarrhea and hepatitis. They found that biomarkers of immune response to infection were “significantly higher” among those with PTSD, which may show their immune systems have been compromised.

The researchers said further study would be important for service members and veterans with PTSD in terms of developing appropriate psychological and drug-based treatments, “particularly in the wake of an increasing number of military veterans returning home after recent wars worldwide.”

The study was published in the April edition of the Proceedings of the National Academies of Science.