School Shooting Study Shows Genetic Links to PTSD

Sept. 6, 2011 -- A study of college students before and after a campus shooting has helped to pinpoint genes that may influence whether or not a person will develop lasting psychological problems after trauma.

In 2008, Holly Orcutt, PhD, an associate professor of psychology at Northern Illinois University, in DeKalb, was collecting information on more than 1,000 undergraduates for a study on trauma after sexual abuse when her plans took a dramatic turn.

On Feb. 14, a suicidal gunman walked onto the stage that fronted a campus lecture hall and opened fire on students and teachers attending an ocean sciences class there. He killed five students and wounded 21 others.

Violence and Opportunity

Many of the women in Orcutt’s trauma study were freshman and sophomores and were on campus the day of the shooting. A few were in the lecture hall where it happened.

“And I said ‘wait a minute, I’m sitting on a gold mine in terms of trauma research,’” she says. “What I can do to make a difference in this tragic situation is to try to make the most of what I have to help people.”

Within days, she had secured funding and permission from the University to reinterview the students in her study to capture details about how they were coping.

Life became laboratory -- a rare opportunity in trauma studies.

“You can hardly randomly assign people to trauma in real life,” says Avshalom Caspi, PhD, a professor of psychology, neuroscience psychiatry, and behavioral science at Duke University’s Institute for Genome Sciences and Policy in Durham, N.C.

“That makes trying to identify the genes involved in sensitivity to stress very difficult because we can’t randomly assign people to stress. We have to observe what happens in nature,” he says.

Observing natural trauma usually means asking people to remember what happened to them. Memory can distort actual events.

And one person’s definition of child abuse may be different from someone else’s.

The campus shooting allowed scientists to see what happened after a shared, independently verified event.

“What these very clever scientists have done is they have essentially carried out what is tantamount to a natural experiment,” says Caspi, who with his research partner at Duke, Terrie Moffitt, PhD, first showed that genes could influence the development of depression after stressful experiences.

They were not involved in the current study.

“By capitalizing on the fact that they had data before, there’s a terrible event happening, and following up with these people after,” the researchers had produced very “strong and compelling evidence” of a genetic influence on the development of posttraumatic stress disorder (PTSD), he says.

Genes, Environment, and Trauma

Two years later, Orcutt reached out to Kerry Ressler, MD, PhD, an associate professor at Emory University in Atlanta and an investigator at the Howard Hughes Medical Institute in Chevy Chase, Md., who is working to identify genes that predispose people to developing PTSD.