The chronic fatigue syndrome (myalgic encephalomyelitis)--myth or mystery?

The chronic fatigue syndrome (CFS) or myalgic encephalomyelitis has caused great confusion, misunderstanding and perhaps even mismanagement of many persons presenting with a variety of combinations of ill-defined complaints. The history, possible pathogenesis and clinical features, of what is probably in most instances a post-viral infection syndrome, are reviewed. The recent Centers for Disease Control case definition is summarised and simplified. The need for such uniformity of definition, acceptable to most workers in the field, is emphasised in order to facilitate further studies into the cause, diagnosis, course and treatment of CFS. The difficulty in treating this condition and the currently recommended management are described. Double-blind controlled studies are essential in assessing any proposed new treatment.