The term chronic fatigue syndrome emerged in the course of a workshop1 convened in 1987 by the US Centers for Disease Control (CDC), Atlanta, Ga. The goal of the meeting was to forge a workable case definition of an illness that, just 2 years earlier, had been called chronic Epstein-Barr virusinfection, but for which there was already mounting evidence against an etiologic role for that agent. The case definition that arose represented a consensus opinion rather than rigorously derived criteria. We participants in the meeting had a fairly clear sense of the illness; we just could not delineate it with precision.
Three problems were immediately apparent with the case definition. First, the lack of pathognomonic physical and laboratory findings essentially leaves the definition to rest on a series of unconfirmable symptoms. Second, some of the specifics of the definition are vague and subject to variable interpretation and application,