A new study has found that people living with major depressive disorder are biologically older than people without depression, and that childhood trauma exacerbates this effect. The results illuminate the epigenetic mechanisms that could explain this discrepancy.
Research, which has been published in the American Journal of Psychiatry, shows that major depression can also result in premature aging. Scientists led by Laura Han of the University of Amsterdam Medical Center in the Netherlands studied the DNA structure of people with depression and made an intriguing discovery. They found that the DNA of people with major depression is, on average, 8 months older than that of people without depression. In some cases of severe depression, the biological age was 10-15 years older than the chronological age.
This effect of premature aging was more significant in people who had adverse childhood experiences, such as violence, trauma, neglect, or abuse.
How does depression affect DNA?
The experts examined the DNA of 811 people with depression and 319 people without depression, as a control group. Participants were enrolled in the Dutch Depression and Anxiety Study.
Using blood samples, the researchers examined how the participants’ DNA changed with age. The study revealed that epigenetic changes occurred more quickly in people with depression.
Epigenetics is the study of changes in gene expression that do not affect DNA sequence. Such changes can occur as a result of many factors, including the environment and lifestyle. One of the mechanisms through which epigenetic change occurs is called DNA methylation , that is, when a methyl group is transferred and added to DNA.
In general, the scientists found that people with major depressive disorder had a degree of methylation and epigenetic change that was indicative of older age. More specifically, this means that people with depression were biologically older than people without depression.
The study also found that those who had experienced childhood trauma had a biological average of 1.06 years older than people who had not experienced trauma.
The researchers replicated their findings by examining brain tissue samples.
Epigenetic Clock Goes Faster With Depression
“The fact that we have seen similar results in both blood samples and postmortem brain tissue helps to believe that this is a real effect. What we see is, in fact, an ‘epigenetic clock’, where the modification patterns of the DNA of the body are an indicator of biological age. And this clock seems to run faster in those who are currently depressed or have been very stressed, “explains Laura Han, leader of the work.
According to the expert, this difference becomes more evident as age increases, especially once they reach 50-60 years of age.
The results highlight the biological effect of trauma in early life and the importance of preventive and therapeutic measures when dealing with depression and adverse experiences in childhood.
However, he also notes that more research is needed to strengthen the results. “Of course, these are associations, so we need long-term linked studies (longitudinal studies) to be able to draw conclusions about whether trauma causes epigenetic aging,” Han says.
Reference. Epigenetic Aging in Major Depressive Disorder. American Journal of Psychiatry. Laura KM Han, M.Sc., Moji Aghajani, Ph.D., Shaunna L. Clark, Ph.D., F. Chan, Ph.D., Mohammad W. Hattab, Ph.D., Andrey A. Shabalin , Ph.D., Min Zhao, DDS, Gaurav Kumar, Ph.D., Lin Ying Xie, M.Sc., Rick Jansen, Ph.D., Yuri Milaneschi, Ph.D., Brian Dean, Ph.D .. Published Online: 16 Apr 2018 https://doi.org/10.1176/appi.ajp.2018.17060595
