FM was never associated with ME. ME had a problem with exercise, what we would call PEM, as its cardinal symptom with pain a close second. I was told by a doctor that when he was at the Royal Free during the epidemic the patients would hit the roof when they were touched. A deep burning pain, presumably from lactic acid build up is common and indicates a problem with mitochondrial function which research was beginning to work out.
Then came CFS. The research money went to AIDS, and, especially in the UK, the psyches took over. When I first heard of FM, about then, very gentle exercise was seen as giving the best relief, though many people still needed strong pain killers.
However, as the confusion started, people with CFS but a lot of pain started being told they had FM as well. I believe that this was an artefact of the fact that CFS was so loosely defined and ME with its emphasis on exercise problems, was forgotten.
After decades of this diagnostic confusion, I do not think it is possible to do a meaningful study differentiating FM and CFS because there are no pure samples of patients. If PEM is not taken into consideration, patients with widespread pain are just as likely to have ME not FM and since ME does not need fatigue - I have never experienced 6 months of constant fatigue, rather I experience a collapse after effort, but that is not what the definition of CFS actually says - the CFS group may contain very few people with ME. This is especially insidious since neurological signs are exclusionary to CFS and in some studies this has included a positive Romberg sign which is almost diagnostic of ME!
Until we have very strict research definitions (diagnostic definitions can be much looser) all the research is little better than astrology.
It makes me very angry.
I have not been posting to forums for a while and thought I was well enough to start again but it has not been as easy as I hoped. If I do not reply, it is simply my health and I wish you all well and still hope for a time when we are given the research, respect and consideration we deserve.
Good health to everyone