Yale researchers have discovered a strong link between genes and the likelihood that someone will suffer from post-traumatic stress disorder (PTSD).

Pingxing Xie GRD ’13 and Yale School of Medicine professor Joel Gelernter ’79 found that a particular form of a gene found on chromosome 17 made some people more likely to develop PTSD. They published their results in the November issue of the Archives of General Psychiatry.

“I’m interested in working out what the important genetic effects are for PTSD,” Gelernter said. “Our goal is to figure out what makes some people more vulnerable to PTSD than other people.”

Gelernter, Xie and other researchers collected genetic data from over 6,000 volunteers for five studies on substance dependence. Xie analyzed the serotonin transporter protein gene in 1,200 individuals who had experienced traumatic events. The serotonin transporter protein gene controls the production of a protein that reabsorbs serotonin — a chemical which affects people’s mood, especially anger and aggression — into nerve cells. The team found that individuals with the short allele of the gene, which resulted in lower production of the serotonin transporter protein, were more likely to develop PTSD.

No one had previously examined the allele’s relation to PTSD at such a scale, Gelernter said.

Eight percent of Americans have been diagnosed with PTSD, while 40 to 70 percent of Americans have experienced a traumatic event. Gelernter and Xie found that individuals were more likely to develop PTSD if they had experienced trauma both as a child and as an adult.

Gelernter said he hoped his team’s research and similar studies will lead to better medications and gene-based prevention and treatment for people with PTSD . Medications known as selective serotonin reuptake inhibitors have already been used to treat some PTSD symptoms, Gelernter said.

Xie said she hoped to further study PTSD, as well as other psychiatric diseases such as depression.

Scientists from the University of Connecticut, the University of California at San Diego, the Medical University of South Carolina-Charleston, Harvard University and Boston University were involved with the study. Funding for the research came from the National Institutes of Health and the United States Department of Veterans Affairs.