A new study suggests PTSD may contribute to the rise in strokes in younger adults

The incidence of stroke, a major cause of disability and death, is on the rise in young and middle-aged adults. A new study suggests that PTSD may be a contributing factor.

"There is now a large amount of evidence that stroke is on the rise in young adults aged less than 45. We are still unable to identify the cause of stroke in about half of overall stroke patients below 30 years of age. We need more studies and funding to study this population which forms the future of our country," Dr. Rohan Arora, director of the stroke program at Long Island Jewish Forest Hills said to ABC News.

The new study, published in Stroke, found that young veterans with PTSD had a 36% increased risk for stroke. They also had a 61% increased risk for transient ischemic attack (TIA), a brief, self-resolving stroke-like event that can represent a warning for future stroke.

Post-traumatic stress disorder has gained significant attention over the past few years with health concerns of those near ground-zero on 9/11, the return of veterans from the wars in Iraq and Afghanistan, multiple mass shootings and increased awareness of sexual assault.

Researchers examined over 900,000 veterans with an average age of 30 for thirteen years. Almost 30% of these veterans developed PTSD. They found that those that did were more likely to experience stroke and TIA than those who did not.

"PTSD may lead to the secretion of 'bad chemicals' in the bloodstream that cause inflammation ... causing injury to the arteries leading to clot formation," Arora said. Clot formation is the basis of stroke.

"PTSD also worsens pre-existing high blood pressure and diabetes -- important risk factors for stroke," he added.

Compared to the veterans without PTSD, those with PTSD had higher rates of high blood pressure and diabetes, as well as other known stroke risk factors, such as irregular heart rhythms, diabetes, high cholesterol, smoking and obesity. Still, the occurrence of these conditions was low among all young veterans. They were relatively healthy.

Beyond that, the 36% and 61% increased risk was found when accounting for these factors. The fact that the relationship was strong and significant regardless of these other variables suggests that PTSD plays a unique part in the development of stroke.

"PTSD is a national public health issue," said Lindsey Rosman, Ph.D, the lead author of the study, and assistant professor of Medicine in the division of Cardiology at the University of North Carolina at Chapel Hill.

"We know that young folks are increasingly exposed to direct and vicarious trauma, whether its natural disaster, gun violence or sexual assault. These same young folks don't have the same traditional cardiovascular risk factors for stroke we see in older people," Rosman said.

Rosman said that the digital age exposes people to "indirect trauma."

"Young people can develop PTSD symptoms that are severe and impairing through vicarious trauma. They are continuously exposed to videos of traumatic events that they have the ability to watch over and over again," she said.

The veterans studied were predominantly male and white. Rosman pointed to directions of future research, "It's very important in future studies to look at the role of sex in PTSD and stroke. Women are more likely to experience chronic stress and PTSD, but are known to have a lower stroke risk than men." She also stated, "It's possible other factors that we didn't control for played a role, including sleep disturbance and migraine."

Although the study focused on veterans, Rosman noted, "We did not assess the nature of the trauma and it's possible that our veterans, many of whom were not in combat, experienced more than military trauma. They could have experienced sexual assault and life adversity." Thus, she believes the findings can apply to those who have PTSD whether they are veterans or not.

"Based on this, we need to realize that there is no one-size-fits-all. We need to develop age-appropriate screening and intervention. We need to expand our view when it comes to risk factors," she said.

"Unique mental health issues may be an important part in understanding a young person's risk factors of developing disease."

Dr. Saumya Bhutani is a resident in psychiatry in New York with the ABC News Medical Unit.