Sickness behaviour because of somatic illness is one thing, and ubiquitous to ALL organic illnesses. It's when special pleading is done with CFS as an 'unexplained' (therefore given psychogenic explanation by default) illness that we run into problems. THIS is what the CDC have been doing! They're claiming infections are 'triggers' rather than causational (and not researching into infectious causation, even where the evidence should point them in that direction) and 'stress' or other psychogenic explanation is almost (perhaps even) always resorted to. And, this study above has used unsubstantiable psychogenic causation theory. That makes it problematic, and most likely useless towards researching or theorising Canadian defined ME/CFS.