A comparison of the 1988 and 1994 diagnostic criteria for Chronic Fatigue Syndrome

Chronic Fatigue Syndrome (CFS) is an illness that involves severe, prolonged fatigue as well as neurological, immunological, and endocrinological system pathology. Because the pathogenesis of CFS has yet to be determined, case definitions have relied on clinical observation in classifying signs and symptoms for diagnosis. In an attempt to address various criticisms and inconsistencies in diagnostic criteria, there have been several revisions of the CFS case definition. The current investigation examined the differences between 1988 and 1994 definitions as well as participants who had a psychiatric explanation for their fatigue. Dependent measures included psychiatric comorbidity, symptom frequency, and functional impairment. The 1988 criteria, compared to the 1994 criteria, appeared to select a group of participants with more symptomatology and functional impairment, but these groups did not significantly differ in psychiatric comorbidity. Implications of these findings are discussed.