Major Depressive Disorder (MDD) is one of the most common mental disorders worldwide. About 264 million people of all ages are thought to have one or another kind of depression as stated by the World Health Organization. MDD has been linked with increased cases and death related to heart disease, diabetes, and Alzheimer’s disease.
What was the study about?
A recent study was conducted by a multidisciplinary team of University of California San Francisco scientists with other collaborators from Walter Reed Army Institute of Research. It discovered that the cells of the persons who are suffering from Major Depressive Disorder (MDD) hold a greater degree of methylation than previously thought at certain points on their DNA, in contrast to the healthy people who do not have Major Depressive Disorder (MDD).
Methylation is a process in which DNA is chemically changed at definite points that result in a swipe in the expression of selected genes. DNA methylation clocks are a group of genes that undergo methylation naturally with age but can vary from person to person. The study found that the DNA methylation process in the individual with MDD was raised as opposed to the healthful people.
The investigation involved withdrawing blood specimens from 49 patients who had MDD and also from 60 healthy people with no MDD. Methylation processes were then examined with the help of a numerical algorithm known as the ‘GrimAge’ clock, which is built to foresee a person’s outstanding lifetime based on cellular methylation style. The research that was later issued in Translational Psychiatry on April 6, 2021, found that the person with MDD had a notably elevated GrimAge score, which suggested augmented death risk- a mean of roughly a couple of years on the GrimAge clock, in contrast to healthy people of the same age.
The patients with MDD remained off the medications before the study and had no apparent symptoms of age-associated pathogeny, as they and the normal controls were screened for physical well-being before the start of the study. Lifestyle elements such as smoking and body mass index played no role in the mortality risk, rather the threat continued with the degree of methylation. Those brand new findings proposed that there is an intrinsic biological process that is rushing the cellular aging, which is linked with increased death and morbidity in the patients of MDD.
Previously MDD was thought to be an entirely cerebral or psychiatric illness that is confined to processes in the brain, but the results, shown by this study have changed our accepted perception regarding depression that it is a disorder of the whole body. Patients suffering from post-traumatic disorder also produce a change in the methylation pattern as shown by previous studies. Some people hold hereditary susceptibility to developing certain methylation processes in reaction to stressors.
What can be done in the future?
With the findings from the study, the investigators are hoping to find out if antidepressants or other therapies may decrease some methylation processes linked to MDD, which should, in turn, normalize the cellular decaying method in concerned people before its progression. Further studies in a large group are required to address these questions and to make targeted diagnostics and treatments that will eventually refine patient care.