ME/CFS (the currently accepted name in the US) is a physiological disease. This is beyond dispute, and no longer a debate in the medical and scientific community. At least in the United States.
US CDC: “Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a serious, long-term illness that affects many body systems.”
US National Academy of Medicine: ME/CFS “is a medical — not a psychiatric or psychological — illness.”
New York State Department of Health: ME/CFS is “a multi-system disease associated with neurological, immunological, and energy metabolism impairment.”
Yes, but only very recently so. For example, it’s only a few months ago that the CDC removed language and recommendations that were remnants of the belief that it is psychological. See the article that I linked at the end of the post for some background there (https://www.npr.org/sections/health-shots/2017/10/02/554369327/for-people-with-chronic-fatigue-syndrome-more-exercise-isnt-better). And it’s likely that there are plenty of doctors who haven’t followed these developments closely and would still believe it’s not a physiological disease.
This was intended to be a reply to casebash, who was questioning whether ME/CFS was psychological. It was not meant as a comment on the article itself. My apologies for the confusion.