Richard Border from the University of Colorado at Boulder and his colleagues picked the 18 candidate genes that have been most commonly linked to depression—SLC6A4 chief among them. Using data from large groups of volunteers, ranging from 62,000 to 443,000 people, the team checked if any versions of these genes were more common among people with depression. “We didn’t find a smidge of evidence,” says Matthew Keller, who led the project.Between them, these 18 genes have been the subject of more than 1,000 research papers, on depression alone. And for what? If the new study is right, these genes have nothing to do with depression. “This should be a real cautionary tale,” Keller adds. “How on Earth could we have spent 20 years and hundreds of millions of dollars studying pure noise?”