And in a rare occurrence in genetic research, a British-led international team's finding of a DNA region linked to depression has been replicated by another team from the United States who were studying an entirely separate group of people.
"What's remarkable is that both groups found exactly the same region in two separate studies," Pamela Madden, who led the U.S. team at Washington University, said in a statement.
The researchers said they hoped the findings would bring scientists closer to developing more effective treatments for patients with depression, since currently available medicines for depression only work in around half of patients.
The studies were published in the American Journal of Psychiatry on Monday and both teams reported a strong link between depression and genetic variations in a region called chromosome 3p25-26.
Major depression affects about 20 percent of people at some point in their lives. Severe and recurring depression affects up to 4 percent of people and is notoriously hard to treat.
The World Health Organization has forecast that depression will rival heart disease as the health disorder with the highest disease burden in the world by 2020.