Through studying genetics, researchers have found that nobody inherits depression from his or her parents and that there is no "depression gene" (as far as anyone knows.) There is; however, a clear genetic component of depression that is currently being studied extensively.
In a study of twins, it was found that if one twin has depression, the other is more likely to have it as well when compared to non-twin siblings. "We know there is a heritable quality of both unipolar and bipolar depression," says Dr. John H. Krystal, chair of the department of psychiatry at Yale University School of Medicine and chief of psychiatry at Yale-New Haven Hospital. The exact numbers are still unknown, but it is estimated that one-third to one-half of the reasons why somebody may develop the disease is due to genetics. Researchers were able to find 15 different aspects of the genome associated with depression. These genes are getting and will continue to get a lot of intensive study, thanks to the hard workers at 23andMe. Dr. Steven E. Hyman, director of the Stanley Center for Psychiatric Research at Broad Institute of MIT and Harvard and professor of stem cell and regenerative biology at Harvard University, believes it's unlikely there will be one single genetic marker for depression to be discovered. What we can begin looking at are different risk versions someone may have, making it a statistical matter.
One can have higher risks for depression, but there are other factors that must be taken into consideration since three are other factors that can also lead to depression (i.e. stress. nutrition, and exercise.) "I am more than hopeful that, with enough time and effort, genetics will yield a useful piece of the puzzle," Hyman says. Krystal agrees to his positive forecast and is optimistic about what we'll be able to achieve through studying genetics in the coming years. I agree with both, Hyman and Krystal and I am hopeful. Since different factors in the genome linked to depression have already been found, further studies can be done from here and hopefully lead to new breakthroughs in genetic research on a terrible disease, depression.