From NIH.gov "Fatigue" (last update 24 April 2015): http://www.nlm.nih.gov/medlineplus/ency/article/003088.htm "CFS" is not included in the list of illnesses. Instead, information about fatigue and medication is listed, and then a note about "CFS" (not ME or SEID) is tacked on at the end. And followed immediately by (but presumably as "treatment" for all fatigue): Note: The Wayback Machine has a record of this page dating back to 2001. At that time, the term "chronic fatigue" was used within the general info on fatigue, but neither "chronic fatigue" nor "Chronic Fatigue Syndrome" are listed with fatigue-causing illnesses. The term "chronic fatigue" however links to a page on Chronic Fatigue Syndrome, described as a "condition". (Alternative names includes Yuppie flu.) By 2004, it seems that "chronic fatigue" was replaced with Chronic Fatigue Syndrome on the fatigue homepage. Here too, it's described as a "condition" and is not included in the list of illnesses in which fatigue is a common symptom.