An international genome-wide association study of 200,000 people has established that the risk of post-traumatic stress disorder (PTSD) is heritable, silencing theories that the disorder is solely a social construct. Researchers from more than 130 institutions participating in the Psychiatric Genomics Consortium published their findings online in Nature Communications.
“Based on these findings, we can say with certainty that there is just as much of a genetic component to PTSD risk as major depression and other mental illnesses,” said senior author Karestan Koenen, PhD, associate member of the Stanley Center for Psychiatric Research at the Broad Institute of MIT and Harvard, Cambridge, MA, and a professor of psychiatric epidemiology in the Harvard T.H. Chan School of Public Health in Cambridge.
The study, which used data from 30,000 people with PTSD and 170,000 control subjects, found that genetics accounts for between 5% and 20% of the variability in PTSD after a traumatic event. Additionally, the study revealed PTSD to be highly polygenic, or associated with thousands of genetic variants throughout the genome.
DNA variants at six loci were strongly associated with PTSD risk, according to the study. Two were specific to European ancestry, and one was specific to African ancestry. Three were detected only in men. The six loci suggest PTSD may involve inflammatory and immune mechanisms.
Researchers also developed a polygenic risk score for a person’s risk of developing PTSD after a traumatic event, but they said it is not ready for clinical use. More studies with more diverse datasets are needed, they advised.
“Our long-term goal is to develop tools that might help clinicians predict who is at greatest risk for PTSD and personalize their treatment approaches,” said study first author Caroline Nievergelt, PhD, associate professor of psychiatry at University of California San Diego School of Medicine and associate director of neuroscience at the Veterans Affairs San Diego Healthcare System. “We can’t always protect people from trauma. But we can treat them in the best ways possible, at the best time.”
Nievergelt CM, Maihofer AX, Klengel T, et al. International meta-analysis of PTSD genome-wide association studies identifies sex- and ancestry-specific genetic risk loci. Nature Communications. 2019 October 8;10(1):4558.