Post-traumatic stress disorder is more than just a mental health issue. New research suggests it may also lead to accelerated aging.

Post-traumatic stress disorder (PTSD) is mainly seen as a disease that causes mental anguish, but a new study suggests that people with PTSD may also be at risk of accelerated aging.

“This is the first study of its type to link PTSD — a psychological disorder with no established genetic basis, which is caused by external, traumatic stress — with long-term, systemic effects on a basic biological process such as aging,” said the study’s senior author Dr. Dilip V. Jeste, a professor of psychiatry and neurosciences and director of the Center on Healthy Aging and Senior Care at the University of California San Diego, in a press release.

In the study, published online today in The American Journal of Geriatric Psychiatry, researchers reviewed previous studies that examined the connection between PTSD and early aging.

Since no standard definition of premature or accelerated aging exists, researchers instead focused on three potential signals of faster-than-normal aging — biological signs like shortened telomeres or markers of inflammation, higher rates of medical conditions linked to advanced age, and early death.

Out of 64 potential studies, the researchers identified 22 that were suitable for determining the link between PTSD and the biomarkers and 10 others that could be examined for the condition’s connection to early death.

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The six studies that looked specifically at telomere length in white blood cells found that they were shortened in people with PTSD, compared to those without the condition.

Telomeres are caps at the end of each strand of DNA in the body. They protect the chromosomes, much like the plastic tips on shoelaces. They may also indicate how quickly the body is aging. Each time a cell divides, the telomeres shorten. If they become too short, the cell becomes inactive or dies.

Although the length of telomeres are taken as a sign of aging, the exact connection between their length and PTSD is unknown. Some previous studies suggest that PTSD causes the telomeres to shorten, essentially speeding up the aging process.

Other research, though, indicates that people with shorter telomeres may have a greater risk of developing PTSD after a traumatic event.

In the current study, researchers also found that markers of inflammation were higher in people with PTSD. These included tumor necrosis factor alpha and C-reactive protein.

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In addition, several medical conditions associated with advanced aging were more common in people with PTSD. This included type 2 diabetes, cardiovascular disease, and dementia.

An increased risk of dementia could be caused by severe brain trauma that occurred during combat. But researchers found that non-combat veterans with PTSD were also more likely to have dementia, compared to those without PTSD.

In addition, seven of 10 studies found a link between PTSD and early death. When the results of the studies were grouped together, the researchers estimated that PTSD increased the risk of dying by 29 percent.

Nine of the mortality studies, however, were done in military settings, so the findings may not apply to people with PTSD who are not veterans.

Although the researchers attempted to combine the findings of several studies, there was still a large amount of variability among the research. This makes it difficult to compare the results.

It also means that the effects seen with PTSD could be due to other risk factors — many of which occur alongside PTSD — such as smoking, higher alcohol use, poor diet, and lack of exercise.

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Previous research has found that stress is involved in many aspects of the aging process. This could explain the link that the researchers found between PTSD and early or accelerated aging.

Because of its limitations, the current study was only able to offer hints at what this relationship might be. But the study shows that PTSD may involve more than just the mind.

“These findings do not speak to whether accelerated aging is specific to PTSD, but they do argue the need to re-conceptualize PTSD as something more than a mental illness,” said the study’s lead author Dr. James B. Lohr, a professor of psychiatry at the University of California San Diego, in the press release. “Our findings warrant a deeper look at this phenomenon and a more integrated medical-psychiatric approach to their care.”

During any given year, more than 5 million adults in the United States suffer from PTSD.

While people of all backgrounds can develop PTSD, recent attention has focused on military veterans who served in the Middle East and elsewhere. A large number of them are at risk of developing PTSD.

The National Center for PTSD estimates that in any given year between 11 and 20 percent of veterans of the Iraq War have PTSD.

These people can also develop other mental health conditions that commonly occur alongside PTSD — insomnia, depression, eating disorders, and substance abuse.