WEDNESDAY, April 26, 2017 -- Surviving trauma such as assault, rape or wartime combat can leave a person emotionally devastated. Now, new research suggests your genes may help determine whether you go on to suffer post-traumatic stress disorder, or PTSD.
"Our finding that PTSD is heritable suggests that our genes contain clues for why some people develop PTSD and others do not, despite having experienced a similar event," said lead researcher Karestan Koenen.
The large study found that the genetic risk for PTSD is much higher for women than men. And it adds to evidence that mental ills such as schizophrenia share genetic links with PTSD, said Koenen, a professor of psychiatric epidemiology at the Harvard School of Public Health.
Most people experience some level psychological distress after living through a severe or life-threatening experience. They may replay the event repeatedly in their mind and feel anxious, irritable and unable to sleep, Koenen noted.
"For some people, these symptoms persist and they develop full-blown PTSD. But for many people, these symptoms abate over time, even without treatment," she said.
In the United States, one in nine women and one in 20 men will develop PTSD at some point in their lives, Koenen said.
Genetic studies like this international effort are helpful in several ways, said Koenen.
"Genetics can provide a basis for new treatment development and help us better match treatments to patients," she said.
PTSD's effects extend beyond the mind.
"The disorder itself causes enormous suffering, and there is more and more evidence it has adverse effects on physical health," Koenen said. "People with PTSD are at greater risk of cardiovascular disease, diabetes and dementia."
People with PTSD are also at an increased risk for suicide, hospitalization and substance abuse, Koenen added. But for now, it's too soon to test people for genes involved in PTSD, she said.
"The evidence suggests PTSD is like other common disorders, in that risk is influenced by many, many genetic variants with small effects," she said. "By many, I mean hundreds to thousands."
A New York psychiatrist agreed it's too soon for people to wonder if they've got the "PTSD gene."
"We are not at the point at which people need to think about this themselves. It's really more of a scientific finding," said Dr. Victor Fornari, a psychiatrist at Zucker Hillside Hospital in Glen Oaks.
"We are trying to understand what the biological underpinnings of psychiatric problems are, because psychiatric problems are brain diseases," Fornari said.
"There may be genes that are not specific to one disorder or another that may predispose you to different psychiatric disorders," he said.
This new finding is important, he added, because it appears that an overlap exists between the genetics of people with PTSD and the genetics of those with other psychiatric problems, such as schizophrenia.
For the study, Koenen and her colleagues analyzed genetic data on more than 20,700 people who participated in 11 multi-ethnic studies around the world.
The investigators said they found that among European-American women, genetic factors make up 29 percent of the risk for PTSD. This is similar to the role that genetics play in other psychiatric disorders, the researchers said.
For men, genetics play a substantially lower role in PTSD risk, Koenen said.
Besides schizophrenia, people with genetic risks for bipolar and major depressive disorder also appear to have a somewhat higher genetic risk for PTSD, the study suggests.
The report was published online April 25 in the journal Molecular Psychiatry.
For more on PTSD, visit the U.S. National Institute of Mental Health.
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