Sir Simon Wessely, a professor of psychological medicine at King's College London told Newsweek that there is already "ample evidence that ME/CFS is not the same as depression, but that previous depression increases the risk of developing ME/CFS, which needs explaining, and I would be surprised if genetics does not play some part in this."
He said that while it is understood ME/CFS is not an anxiety disorder, "anxiety can impede recovery."
"The fact that ME/CFS involves both excessive physical and mental fatigue and fatiguability after both physical and mental exertion already tells us that the causes are most likely to be central, i.e., the brain, rather than peripheral—these new findings reinforce that, but we are still a long way from knowing why," he said.
"Unravelling multigenic and multi factorial conditions such as ME/CFS is going to be a long haul, as those who have been researching the genetics of psychiatric disorders have already found out," he added.