Stress and depression in girlsGirls who are more stressed may age more quickly, reports a study from Stanford University in collaboration with Northwestern University and the University of California – San Francisco. The new study finds that girls with a family history of depression exhibit a more pronounced stress response and that their telomeres—a genetic marker of age—appear older. The findings suggest that stress and depression can affect the body.

The researchers evaluated healthy girls aged 10 to 14. Some of the girls had a family history of depression, the rest did not. To test their stress response, the researchers asked the girls to count backwards by 7’s from 100 and questioned them about stressful experiences. To measure the girls’ stress levels, the researchers analyzed their cortisol—a hormone that indicates stress—levels. They also examined the length of the girls’ telomeres. Telomeres are caps found on the ends of chromosomes. Each time a cell divides, the telomere shortens, which allows scientists to use telomeres as a kind of biological clock.

At an age before they were old enough to develop depression, the girls with a family history of depression showed signs of stress and aging beyond that of their peers. The girls with a family history of depression had a more intense physiological response to stress, producing more cortisol than their peers. These girls also had shorter telomeres than the girls without a family history of depression. The telomeres were shorter by what would roughly be six years in adults. However, no research documents typical telomere length in children, so it is not clear if the girls’ telomeres are truly “six years” shorter.

Although the findings link stress, a risk for depression, and shorter-than-typical telomeres, it is not clear which is the causative factor. The researchers suspect that telomere length may predict who goes on to develop depression, but more research is necessary before scientists can draw conclusions.

The study is the first to consider telomere length in children at-risk for depression. This research could lead to advanced screening methods for depression or could help identify ways to prevent depression, like reducing stress.

This research is published in the journal Molecular Psychiatry.

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