If the extent of human suffering were used to decide which diseases deserve the most medical attention, then depression would be near the top of the list. More than 350 million people are affected by depression, making it one of the most common disorders in the world. It is the biggest cause of disability, and as many as two-thirds of those who commit suicide have the condition.
Depression research also gets a great deal less funding than that gobbled up by cancer. The US National Institutes of Health pumped about US$5.3 billion into cancer research in 2013 — a stark contrast to the $415 million it spent on depression research and the $2.2 billion on mental-health research as a whole.
Jonathan Flint, a psychiatrist at the University of Oxford, UK, who has been looking for genetic links to depression for nearly two decades, says that some colleagues ask him why he is still working on the problem. “What has held back the entire field is the belief that it’s intractable,” he says. “What is the point of doing something if you’re not going to get anywhere with it?”