A subgroup analysis of cognitive-behavioral treatment studies

Several studies of graded activity-oriented cognitive behavioral treatment for chronic fatigue syndrome (CFS), all conducted in England, have reported dramatic improvements in functioning and substantial reductions in symptomatology. On the other hand, cognitive behavioral intervention studies conducted in Australia and the United States have not found significant improvements in functioning or CFS symptoms. Based on a review and synthesis of data from these clinical trials, naturalistic outcome investigations, and illness comparison studies, this articles argues that two CFS subgroups, distinguished by functional status and symptom severity, may account, in part, for the differences in outcome in cognitive behavioral treatment studies. It is also argued that differences in treatment duration may have influenced clinical outcomes. This article concludes with recommendations for specific cognitive behavioral interventions in CFS.