Depression affects almost 7% of the US population, 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, but now researchers are finding that there may be more to the physical effects of depression than previously studied.
Expressly, researchers from the UK have found evidence that depression doesn’t just change our brains, but may affect individuals on a cellular level, and alter our DNA and the way our cells generate energy.
A team of researchers investigated the genomes of more than 11,500 women, with the hopes of finding genes that might contribute to the risk of depression. However, they discovered a signature of metabolic changes in their cells that appears to have been triggered by the disease.
How Depression Affects Your DNA
The discovery began with an examination of the DNA of over 11,000 people, many of whom had a history of stress-related depression. Healthy controls were also included in the research for comparison.
This group of researchers then noticed that stress-related depression correlated with an increase in the amount of the cell’s second genome (mitochondrial DNA).
They also made a notable discovery that women who had stress-related depression; like depression that’s associated with some kind of adversity during childhood such as sexual abuse, had more mitochondrial DNA (mtDNA) than their peers.
Mitochondria are the ‘powerhouse organelles’ that provide the energy for the rest of the cell. Thus, the increase in mitochondrial DNA led the researchers to believe that the energy needs of their cells had changed in response to stress.
The researchers were surprised at the observation that there was a difference in mitochondrial DNA, that it took them a long time to convince themselves it was real, and not an artifact.
After going back over their results, the researchers also found that the women with stress-related depression had shorter telomeres (Telomeres are the caps at the end of our chromosomes that naturally shorten as we age) than the healthy women. This discovery led the team to question whether this process had been sped up by stress.
The scientists then took this one step further and tested the molecular changes in mice that were subject to four weeks of stress. They also found that the mice exhibited the expected increase in mitochondrial DNA, and also that their telomeres had reduced in length.
Telomeres aid to shield our chromosomes from degradation and thus the loss of genetic information. Every time a cell makes a copy of itself, the length of the protective telomere gets a little bit shorter until the cell can no longer divide.
The erosion of telomeres in the stressed mice indicates that stress can decrease life expectancy. Furthermore, the researchers also discovered that the changes in both telomere-length and the increase in mitochondrial DNA are largely reversible, because, after the mice were free from stress, their DNA also recovered.
There are plenty of causes for stress which decreases the efficiency of the mitochondria, and as a result, the body creates more to protect its metabolism. In some sense, stress and depression may be the body’s response to environmental stress.
The good news is that the research in mice showed that the effects of stress are also partly reversible, and there is a now hope that the research will help point out biomarkers of stress and its consequences.
It’s still very early, but soon enough, looking at mitochondrial DNA levels could help to reveal whether someone has recovered from a trauma.
It’s becoming increasingly clear that the things that affect us emotionally also affect us on a biological level, and stress-induced depression, classically considered being a mood disorder, having these cellular-level effects on the body.
Earlier this year, a separate team of researchers showed that childhood trauma could alter cellular aging. Similarly, in November 2014, scientists also revealed that meditation and yoga can actually help maintain telomere length.
The research is still going on for more answers, as there’s no evidence as yet that these types of changes are permanent or will be passed on to future generations.
This study has also an exciting potential for future treatment of depression, since the molecular changes in the DNA are reversible, and there is now the possibility to assess how successful treatment is on a molecular level.