A new hypothesis of chronic fatigue syndrome: Co-conditioning theory.



Hi gracenote - I'm unaware of the origins of the Fukuda criteria, but I think it's generally pretty common practice to exclude people with so-called "comorbid" diseases from the study of most illnesses, not just CFS. Probably there are cases where researchers might want to study one or more disorders that commonly arise together, most often probably in psychiatry (anxiety + depression, OCD + schizophrenia, etc.), or maybe complications of AIDS and things like that, but as a rule I think researchers tend to want to isolate the problem under study as much as possible just as a basic practice or even tenet of good science. I think it's commonly said, however, that CFS is a "diagnosis of exclusion" clinically, and that's mainly what I was referrring to, at least.
I know that with drug clinical trials, most have "inclusion and exclusion" criteria....some stricter than others. http://clinicaltrials.gov/ct2/home