Scientists at the University of Edinburgh have identified more than a dozen new genetic variants associated with depression, offering more details of the influence genetics has on the condition, which affects more than 322 million people worldwide.
The study — funded by the science charity Wellcome Trust — was published in the journal Nature Communications and used data from more than 300,000 people that are part of the UK Biobank. Researchers identified almost 17 genetic variants associated with depression, and the findings were then replicated against data from a similar-sized dataset that consisted of 23andMe customers who consented to participate in research.
While twin studies have long shown a strong genetic influence for depression, pinpointing the genes and genetic variants involved has been elusive until only the last few years. Access to new and very large data sets is revealing genetic associations that could not be seen before in smaller studies.
“These new findings help us better understand the causes of depression and show how the UK Biobank study and big data research has helped advance mental health research,” said Professor Andrew McIntosh, Ph.D., of the University of Edinburgh’s Centre for Clinical Brain Sciences and the lead author of the study.
The UK Biobank data includes individuals with depression classified in three different categories: clinically diagnosed major depressive disorder, self-diagnosed “probable” major depressive disorder, and a third category defined as broad depression that may also include traits such as anxiety. The researchers found associations across all three categories and identified 17 genetic variants associated with depression. While a few of these variants have been identified in other studies to be associated with depression, 14 of the associations are new. Those genetic variants influenced genes involved in the function of synapses in the brain.
“This study identifies genes that potentially increase our risk of depression, adding to the evidence that it is partly a genetic disorder,” said David Howard, Ph.D., a co-lead author of the study and a Research Fellow at the University of Edinburgh’s Centre for Clinical Brain Sciences. “The findings also provide new clues to the causes of depression and we hope it will narrow down the search for therapies that could help people living with the condition.”
Separate to this work, 23andMe has worked on other studies investigating depression. In 2016, along with Massachusetts General Hospital and Pfizer, we published findings in what was by far the largest study of its kind focused on major depressive disorder. In that study, researchers identified 15 new genetic regions linked to depression. And last year 23andMe launched a depression and bipolar disorder study, quickly enrolling 15,000 people with major depressive disorder. That work is ongoing, and we look forward to continuing to contribute to advances in depression research.