What causes major depression?

A team of researchers is collecting DNA and clinical data from 24,000 people with recurrent major depression and 24,000 healthy controls, aiming to pinpoint at least 30 specific genetic risk factors for the disorder. This matters because major depression is not a single disease but a broad syndrome with multiple underlying biological pathways. Current treatments are blunt tools, partly because the genetic architecture of depression remains largely unknown. Previous work by this group identified the first confirmed genetic risk locations, but larger samples are needed to find more. The current sample of 12,000 cases is too small. If successful, this fundamental science project will transform the biological understanding of depression. Knowing which genes increase risk—and how they interact—could eventually allow researchers to subgroup patients by biological mechanism rather than symptoms alone. That could lead to more targeted treatments and better clinical trial design. The project is primarily curiosity-driven: it seeks to map the genetic landscape of a common, poorly understood condition. Similar fundamental genetic studies of other diseases have later enabled drug discovery and personalised medicine, though no immediate clinical application is promised here.