Spence VA, Abbot NC
University Department of Medicine, Ninewells Hospital, Dundee, UK
Judith Prins and colleagues’ report (1) leaves the clear impression that there is a powerful case for the provision of CBT as a specific therapy for CFS. However, careful assessment of published studies suggests that this impression is not evidence-based. The initial review of reports by Best and Stevens for the UK Research and Development Directorate, South and West, in 1996, showed five studies with limited methods from which little about efficacy could be concluded. Subsequently, a Cochrane review to 1998 (2) could identify only three randomised controlled trials with acceptable methods: one supported (3) and one did not support (4) the use of CBT, although neither controlled for therapist exposure, and the third (5) used a relaxation control.
Thus, with Prins and colleagues’ study, there are two randomised controlled trials in which CBT has been compared (in a pooled total of 113 patients) with an active, although not indistinguishable, intervention (110 patients). The two trials show significant benefits on the primary outcome measures, but conclusions about efficacy must be tentative in view of the paucity of trials; the small number of patients involved; the difficulties inherent in comparing CBT — which included a graded exercise component in both trials — with control interventions, such as relaxation or group support; and, importantly, the potential effect of publication bias. No conclusions can be made about the effectiveness of group CBT (the only cost-effective option in the long term) or the generalisability of CBT to the various subgroups of patients, such as those with severe or long-term disability.
We suggest that the state of current evidence could be more rigorously described as follows: in the absence of any available medical treatment for CFS at present, these two trials together provide a small amount of evidence that CBT (or an equivalent beneficial patient-therapist encounter given on a one-to-one basis) can improve, but not cure, some physical symptoms in some members of the subgroup of CFS patients well enough to attend an outpatient clinic. This description is neither crisp nor appealing, but it more closely represents the true evidential picture.
- Prins JB, Bleijenberg G, Bazelmans E et al. Cognitive behaviour therapy for chronic fatigue syndrome: a multicentre randomised controlled trial. Lancet 2001; 357: 841–7.
- Price JR, Couper J. Cognitive behaviour therapy for adults with chronic fatigue syndrome (Cochrane Review). In: The Cochrane Library, Issue 2. Oxford: Update Software, 2000.
- Sharpe M, Hawton K, Simkin S et al. Cognitive behaviour therapy for the chronic fatigue syndrome: a randomized controlled trial. BMJ 1996; 312: 22–6.
- Lloyd AR, Hickie I, Brockman A et al. Immunologic and psychologic therapy for patients with chronic fatigue syndrome: a double-blind, placebo-controlled trial. Am J Med 1993; 94: 197–203.
- Deale A, Chalder T, Marks I, Wessely S. Cognitive behaviour therapy for chronic fatigue syndrome: a randomized controlled trial. Am J Psychiatry 1997; 154: 408–14.
Comment by ME Research UK
Several articles in the medical literature, including recent opinion pieces on the MEDLINE database, present the impression that there is now a powerful, perhaps overwhelming, case for the provision of cognitive behavioural therapy (CBT) as a specific therapy for ME/CFS patients. This investigation examined the scientific literature to determine whether this impression is based on sound scientific evidence.
A systematic review of all clinical trials of CBT in ME/CFS was conducted using standard medical databases and review techniques. In fact, there are only 2 randomised clinical trials, both showing statistically significant benefits on the primary outcome measures, which have compared CBT (in a pooled total of 113 patients) with an ‘active’, though not indistinguishable, intervention (110 patients).
The evidence for the routine use of CBT for ME/CFS patients is sparse, and does not justify many of the claims made for this intervention. Conclusions about efficacy must be tentative given the paucity of trials; the relatively small number of patients involved; the problems inherent in comparing CBT, which included a graded exercise component in both trials, with control interventions, such as relaxation or group support; and, importantly, the potential effect of publication bias.