Earlier quoted context omitted.
> doctors dismiss patients as crazy or "making it up." I don't think that's true, at least not in my experience anyway. People (myself included) are too quick to conflate "all in your head" with "making it up". Things "in your head" can and do have real, physical, life-limiting, effects. If it turns out that ME/CFS doesn't has a physical marker, then what? There may never be a way to verifiably test for it other than…
> If it turns out that ME/CFS doesn't has a physical marker, then what? The problem is that ME/CFS is similar in presentation to other conditions such as for example certain kinds of depression. The difference is that exercise is thought to help with those conditions and exacerbates ME/CFS. Thus there are two different groups of people, one who you are helping by encouraging them to exercise and one who you are harmi…
It's proven to be the case. A repeat cardiopulmonary exercise (2-day CPET) is currently the only widely replicated biomarker for ME/CFS. Only ME/CFS shows a reduction in performance and a lowering of ventilatory threshold on the second day. Anyone else (sedentary, cancer, heart or lung disease, MS, depression) will show an improvement. [1]
A study this year showed a striking effect looking at the metabolites in urine after exercising female ME patients vs sedentary healthy controls. The ME patients just did not excrete metabolites as the healthy controls did. [2]
"This indicates that ME/CFS patients have a general metabolic dysregulation that is part of their exercise intolerance and PEM in which altered metabolic excretion is a contributing factor."
There's also a very simple clinical discriminator between ME/CFS and depression. If you ask a depressed person what they would do if they were suddenly cured, their answer will be "Not sure, I don't know, I can't think of anything, nothing really." If you ask someone with ME/CFS the same question, the response would be "Go to the shops, drive my car, walk on the beach, see my friends... etc".