[Definition of the chronic fatigue syndrome and its issues].

This article reviewed Definition of CFS proposed by CDC 1988. There are several issues in Definition for CFS of CDC. It is presented that other chronic clinical conditions have been satisfactorily excluded, including preexisting psychiatric diseases in (2) of major criteria. However, fibromyalgia can not be excluded from the fifth symptom of minor criteria, myalgia, and also depression from the ninth symptom. It is practically difficult to define impairment of average daily activity below 50% of the patient's premorbid activity level for a period of at least 6 months, as shown in (1) of major criteria, and it is not adapted for a first visit patient. Definition for CFS of CDC has been discussed on EBV infection, but not written on postviral fatigue syndrome and myalgic encephalomyelitis. Especially whether epidemic type of CFS is present or not was not discussed. Diagnostic criteria of CFS is necessary for clinical practice.