I am both a health care professional (not a physician or someone who can prescribe medicine) and a father of a son who suffered terribly with CFS/ME and after 8 + years is actually doing quite well. The problem with diagnosing ailments in the human body is that we are so complex. Our nervous system alone is mathematically the most complex system in the universe and that is not taking into account all of our other systems. No offense to some who have posted, but there simply is not enough knowledge of such a complex system to definitively assign certain diagnosis to a cluster of symptoms especially those associated with something like CFS/ME. In fact the latest research is placing CFS/ME, Chronic Pain, Fibromyalgia, Non-epileptic seizure disorders, "Psuedo-stroke", hemiplegic migraines, RSD, Migraines in general and others yet to be clearly defined under the umbrella of centrally sensitized disorders. This means that that subconscious brain has an increased sensitivity to the person's environment or any stimuli (external or internal) that find their way into the processing centers of the brain. The brain processes and "interprets" this information and then creates a response. Pain for some, fatigue for others, nausea/reflex, weird sensations, cognitive issues/brain fog, sweating, temperature intolerance, anxiety, weakness, balance issues/dizzyness and more. Ultimately these "symptoms" are warning bells going off to alert your conscious brain of an "interpreted threat". To understand this in CFS/ME means that you may have a variety of symptoms including those not noted on the criteria. The criteria that have been developed are inclusive NOT exclusive. This means that you can have any or all of the criteria, but that it does not mean you have to ONLY have them to fit the diagnostic criteria. In addition you can have the same criteria and still have something else (mononucleosis, post concussion, chemo brain). So a really good physician of any kind will use the best of research available, but partner it with the best of their and others experience and then consider the patients values as they deliver care to the single patient that is in front of them. This is by definition Evidence Based Medicine. The term has been hijacked to mean only the research and only specific diagnostic criteria for specific diseases. In the case of a broken bone, appendicitis, stomach flu and sinus infections the research can be very accurate because the problems are not very complex. In the case of CFS/ME, Complex Regional Pain Syndromes, Chronic Pain or any Neurological based symptom disorder without conclusive testing the research is less exact and the experience of the clinician or those around them play a much greater role. In short, with diagnosis like CFS/ME there is far more gray than there is black and white. Anyone who tries to treat is a black and white will most likely fail and any patient who views it as black and white will only produce more anxiety.