I mean, TFA (among others) have made the case that ME/CFS is linked to (if not outright caused by) a number of specific kinds of physical dysfunction... but it'

I mean, TFA (among others) have made the case that ME/CFS is linked to (if not outright caused by) a number of specific kinds of physical dysfunction... but it's true that fatigue is a symptom of countless illnesses, so it gets difficult to figure out which patients are suffering from which conditions. Hence what happened in this study when they tried to narrow it down to a pool of ME/CFS patients :P