The cognitive-behavioural model of ME/ CFS postulates that fear-based avoidance behaviour and physical deconditioning can explain many of the symptoms and impairments associated with the illness. However, a thoughtful essay by Dr Fred Friedberg of Stony Brook University, New York (published in the Bulletin of the IACFS/ME) has examined the assumptions underlying this model and raised important critical issues. His central thrust is that although cognitive behavioural therapy (CBT) has a role in reducing symptoms and improving functioning, important matters surrounding the clinical trial evidence remain to be resolved.
First, there is considerable doubt about whether avoidance behaviour and physical deconditioning are indeed causal factors in the illness; for example, there is evidence to show that ME/CFS patients are not exercise phobic, and are not more physically deconditioned than comparable healthy people. Again, evidence from a recent systematic review (Cochrane Collaboration 2008 http://www.ncbi.nlm.nih.gov/pubmed/18646067) has indicated that approximately 40% of patients benefit from CBT, while the placebo response rates in ME/CFS intervention trials have averaged 20%. This indicates that while CBT appears to be superior to placebo, less than a majority of patients actually benefit from it, an important concern that is not commonly addressed.
Another point highlighted by Dr Friedberg concerns the true clinical significance (rather than statistical significance) of self-reported “improvements” measured in trials of CBT; it is not clear in many cases whether these represent illness improvement or simply better coping, or some combination of the two. And, crucially, it is important to know whether real world clinical improvements occurred; for example, whether patients’ activity levels actually increased, or whether their employment status changed for the better. As he points out, it is time for an objective, balanced assessment of the effectiveness of CBT.
Reference: Cognitive-Behavioral Intervention in Chronic Fatigue Syndrome: Benefits, Limitations, and Open Questions. Friedberg F. Bulletin of the IACFS/ME 2008; 16 (4).