High risk for depression gives young girls a higher stress response and shorter telomeres, a marker for aging, than low risk peers.
Whether stress, depression or changes in the body come first has long been unclear to scientists. So psychologists at Stanford, Northwestern University and the University of California, San Francisco studied healthy girls at high risk for developing depression to try and find out.
They looked at these girls because they have a family history of depression, were stressed out, and responded to stress by releasing much higher levels of the hormone cortisol.
The study found that these girls also had telomeres that were shorter by the equivalent of six years in adults.
Telomeres are caps at the ends of chromosomes. Whenever a cell divides to reproduce, the telomeres get a bit shorter.
The length of telomeres is like a biological clock corresponding to age. Telomeres also shorten as a result of exposure to stress.
Scientists have previously observed links between shorter telomeres and premature death, more frequent infections and chronic diseases.
Which Comes First?
So which came first: stress, depression or premature aging? These otherwise healthy girls showed signs of stress and premature aging before any of them were old enough to develop depression.
The researchers looked at 10- to 14-year-old healthy girls with a family history of depression, comparing them with healthy girls without that history. The girls’ response to stress tests was measured, by asking them to count backwards from 100 by 7’s, and interviewing them about stressful situations.
Before and after the test, the team measured the girls’ cortisol levels. They also analyzed DNA samples for telomere length.
Before this study, “No one had examined telomere length in young children who are at risk for developing depression,” said Stanford psychologist Ian Gotlib.
Six Years of Aging
Healthy but high-risk 12-year-old girls had significantly shorter telomeres, a sign of premature aging.
“It’s the equivalent in adults of six years of biological aging,” Gotlib said, but “it’s not at all clear that that makes them 18, because no one has done this measurement in children."
In other work, Gotlib and the team are investigating stress reduction techniques and their effectiveness for girls.
Neurofeedback and attention bias training, which is redirecting attention toward the positive, seem promising. Other investigators are studying techniques based on mindfulness training.
The researchers also continue to monitor the girls from the original study. “It’s looking like telomere length is predicting who’s going to become depressed and who’s not,” Gotlib noted.
What can a concerned parent do? Gotlib said that research shows exercise can delay telomere shortening in adults, and recommends that high-risk girls learn stress reduction techniques.
“Telomere length and cortisol reactivity in children of depressed mothers.” Molecular Psychiatry advance online publication 30 September 2014; DOI: 10.1038/mp.2014.119
Top Photo by Sascha Kohlmann