Introduction - The Chronic Fatigue Syndrome: A Comprehensive Approach to its Definition and Study

Keiji Fukuda, M.D., M.P.H., Stephen E. Straus, M.D., Ian Hickie, M.D., F.R.A.N.Z.C.P., Michael C. Sharpe, M.R.C.P., M.R.C. Psych., James G. Dobbins, Ph.D., Anthony L. Komaroff, M.D., F.A.C.P. and the International Chronic Fatigue Syndrome Study Group

From the Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia; Laboratory of Clinical Investigation and Division of Microbiology and Infectious Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland; School of Psychiatry, Prince Henry Hospital, University of New South Wales, Sydney, Australia; University of Oxford Department of Psychiatry, Warneford Hospital, Oxford, United Kingdom; and Division of General Medicine, Brigham and Women's Hospital, Harvard University, Boston, Massachusetts. Abstract.

The complexities of the chronic fatigue syndrome and the methodologic problems associated with its study indicate the need for a comprehensive, systematic, and integrated approach to the evaluation, classification, and study of persons with this condition and other fatiguing illnesses. We propose a conceptual framework and a set of guidelines that provide such an approach. Our guidelines include recommendations for the clinical evaluation of fatigued persons, a revised case definition of the chronic fatigue syndrome, and a strategy for subgrouping fatigued persons in formal investigations. We have developed a conceptual framework and a set of research guidelines to use in studies of the chronic fatigue syndrome. The guidelines cover the clinical and laboratory evaluation of persons with unexplained fatigue; the identification of underlying conditions that may explain the presence of chronic fatigue; revised criteria for defining cases of the chronic fatigue syndrome; and a strategy for subdividing the chronic fatigue syndrome and other unexplained cases of chronic fatigue into subgroups.