While ME/CFS and fibromyalgia have overlapping symptoms – including cognitive difficulties, sleep problems, and fatigue, research has identified underlying biological differences between the two diseases.
Despite this, a recently published article – in the title at least, suggests that “ME/CFS and fibromyalgia are indistinguishable” when looking at the proteins in the fluid that surrounds the brain and spinal cord (cerebrospinal fluid).
However, looking more closely at the methods used, the research team did not actually compare ME/CFS with fibromyalgia- they compared 15 people who met the Fukuda criteria for CFS, with 15 people who met both the Fukuda criteria for CFS, and the 1990 case definition for fibromyalgia.
While the results of the study do indeed show that there was “no clear separation of the two groups” when looking at the proteins in their cerebrospinal fluid – this does not provide clear evidence that ME/CFS and fibromyalgia are indistinguishable.
The authors of the paper recognise that more research is needed comparing the cerebrospinal fluid of those who have ME/CFS, with those who have fibromyalgia without also meeting diagnostic criteria for ME/CFS.
ME Research UK also notes that in future studies, the ME/CFS diagnostic criteria used – unlike the Fukuda criteria, should require post exertional malaise as a symptom for diagnosis to be made.