UCSD and VA researchers find possible genetic links for susceptibility to PTSD

PTSD illustration

By analyzing the genomes of more than 250,000 military veterans, a team of scientists led by researchers at UC San Diego and the Veterans Affairs San Diego Healthcare System has identified 18 specific positions on chromosomes, known as loci, that appear to be associated with post-traumatic stress disorder.

The findings validate the underlying biology of PTSD and its relationship to anxiety and depressive disorders and provide potential new targets for treatment, the authors wrote in the Jan. 28 online edition of Nature Genetics.

PTSD is a serious mental disorder that can occur after exposure to extreme, life-threatening stress. It is estimated that half to more than three-quarters of Americans experience traumatic events during a lifetime, but most do not develop PTSD. According to the researchers, lifetime prevalence for PTSD is about 7 percent, but it is much higher among veterans, which suggests people have varying degrees of resilience to stress and vulnerability to the disorder.

“We’re very intrigued by the findings of this study, for example, as they pertain to the genetic relationships between different kinds of PTSD symptoms,” said co-principal investigator Dr. Murray Stein, a professor of psychiatry and family medicine and public health at the UCSD School of Medicine and a psychiatrist at VASDHS. “It also shows the huge value of the Million Veteran Program in facilitating research important to the care of our military veterans.”

The research team conducted studies of more than 250,000 people of European and African ancestry participating in the Million Veteran Program, a U.S. Veterans Affairs-sponsored effort launched in 2011 to learn how genes, lifestyle and military exposures affect health and illness. More than 825,000 U.S. veterans have joined.

The scientists surveyed veterans’ electronic health records for diagnosed cases of PTSD and for symptoms such as recurrent intrusive memories of traumatic events, difficulty sleeping, self-destructive behaviors and severe emotional distress or physical reactions to reminders of traumatic events.

Susceptibility to PTSD has long been known to be heritable, according to the researchers. Though symptoms of PTSD are extremely diverse, their genetic overlap is high — an insight into the disorder’s underlying biology.

The researchers identified multiple genes repeatedly implicated in different PTSD phenotypes — observable traits — indicating that the genes were key players in development of the disorder and that they might be suitable targets for
therapeutic drugs.

“These findings give us new insights into the biological basis of PTSD and point to some possible next steps for testing new treatments,” said co-principal investigator Dr. Joel Gelernter, a professor of psychiatry, genetics and neuroscience at the Yale University School of Medicine and VA Connecticut Healthcare System. ◆