Depression affects almost 7% of the US population, according to the Depression and Bipolar Support Alliance(1) and the effects of it can be more than just psychological.
Neurological and physical effects of depression can include trouble concentrating, insomnia or hypersomnia, excessive weight loss or weight gain, and even panic attacks(2).
But now researchers are finding that there may be more to the physical effects of depression than previously studied. Specifically, it may affect individuals on a cellular level.
How Depression Affects Your DNA
A major study from the Wellcome Trust Centre for Human Genetics examined the genomes of more than 11,500 women. They were hoping to find evidence that depression can have a genetic root – that something in our genes may predispose us to developing or not developing the mental illness.
What they found instead was a signature of metabolic changes in the study participants cells that appears to be caused by depression itself.
Specifically, women who had depression relating to external factors – such as childhood abuse or sexual trauma – had more mitochondrial DNA, or mtDNA, than those who did not.
Mitochondria are organelles which provide energy to cells. Researchers believe that stress and trauma had caused the cells of these women to need increased energy, essentially changing their stress response on a cellular level.
Lead researcher Jonathan Flint said in a recent press release that:
“We were surprised at the observation that there was a difference in mitochondrial DNA. So surprised it took us a long time to convince ourselves it was real, not an artefact.”(3)
Depression Shortens Telomeres
When the researchers on the study re-examined their results, they noticed another consistency: women with stress-related depression had shorter telomeres than women without stress-related depression.
Telomeres are essentially caps at the ends of our chromosomes which protect DNA. They shorten naturally with age, which caused the research team to question whether the shortening process of telomeres was sped up by stress or trauma.
To confirm this hypothesis, they decided to test it in a mouse model. Over a period of weeks, they placed mice in stressful situations and monitored them for any genetic or cellular changes.
Once again, they were surprised to have their hypothesis confirmed by the mouse experiment. Not only did the stressed mice have an increase in mitochondrial DNA by the end of the trial period, but they also had shorter telomeres than the control group(4).
While this study gives only a “snapshot” of the relationship between depression and our DNA, it’s not the first to make the connection between stress, mental illness and change at a cellular level.
Earlier this year, a team of researchers reported that trauma in childhood can alter the way your cells age(5).
The good news is that the damage is at least partially reversible; a 2014 study, for example, found that mindfulness meditation and yoga can actually help maintain telomere length despite stress(6).
Emotional Stress and Rate of Telomeres Shortening