Depression is caused by a combination of factors, biological predisposition triggered by environment, which makes the disorder so complex.
Now, in an attempt to understand the biological underpinnings of depression, a recent study revealed 15 locations in the human genome associated with the development of major depressive disorder. The study, published in Nature Genetics, spanned nearly 460,000 participants, and showed that the genetic regions linked with depression correspond with developmental areas of the brain.
Researchers from Massachusetts General Hospital analyzed the genetic variations of 75,607 people of European ancestry who self-reported being diagnosed or treated for depression and 231,747 healthy controls. The data came from people who had purchased their genetic profiles via Genomics Company 23andMe and allowed the company to anonymously use their information for research purposes.
The profiles from both groups were analyzed for single nucleotide polymorphisms (SNPs), variations in a single nucleotide that occurs at a specific position in the genome. The researchers found 17 SNPs linked to depression at 15 genome locations. One SNP was found to affect a region of the brain involved in the function of the amygdala, which governs emotions and fear, and is implicated in other psychiatric disorders, like anxiety. The findings were validated with a second round of analyses, using 45,733 people who self-reported having depression and 106,354 people who did not.
“We hope these findings help people understand that depression is a brain disease, with its own biology,” said Roy Perlis, M.D., study co-author, of Massachusetts General Hospital. “Now comes the hard work of using these new insights to try to develop better treatments.”
Although any new treatments is a far-off concept, this research helps advance the study of depression’s genetic origins.
Globally, an estimated 350 million people of all ages have depression, according to the World Health Organization. An estimated 15.7 million adults aged 18 or older in the U.S. had at least one major depressive episode in the past year, according to 2014 data from the National Institute of Mental Health.
