Everyone's biological clock is ticking, but for some it ticks faster. In veterans with post-traumatic stress disorder (PTSD), the hands seem to get an extra push. In the largest study to date, covering more than 45,000 US veterans, researchers found that PTSD is linked to accelerated epigenetic aging: that is, the body's cells look older than their passport age would suggest.
Epigenetic clocks are not a device on the wall but algorithms that estimate biological age from chemical marks on DNA. These marks, like notches on a tree, accumulate over the years, but stress can add them faster. The researchers used five different algorithms, each looking at its own set of marks. And by all five clocks, people with PTSD turned out to be "older" than their peers without trauma.
Why does this happen? Excess weight is partly to blame. People with PTSD are more likely to have obesity, and adipose tissue itself accelerates aging. When the scientists accounted for body mass index and diabetes, the link weakened but did not disappear, which means stress also acts directly, through inflammation and hormones.
These results are not a verdict but a warning. If psychological trauma accelerates the biological clock, then timely help can slow it down. Treating PTSD is not just about peace of mind; it is also about the health of the whole body.
The GrimAge epigenetic clock was trained to predict time to death, so its link to PTSD may reflect a real risk of premature mortality in veterans with this disorder.
In Neal Stephenson's novel Seveneves, psychological stress after a catastrophe leads to accelerated aging in survivors, echoing the idea that trauma affects biological age.
Not published on arXiv. Here are its page, the PDF and the formalization: you can check it yourself, not only read our account.