Comment on: Can CBT substantially change grey matter volume in chronic fatigue syndrome? [Brain. 2009]
Sir, In their reply to Dr Bramsen, De Lange et al. (2008) use a type of circular reasoning: cognitive behavioural therapy (CBT), they say, has previously been shown to be ‘effective’ for chronic fatigue syndrome (CFS) so the change they measured must be due to CBT.
First, it needs to be pointed out that CBT is far from a panacea for CFS. A recent meta-analysis (Malouff et al., 2008) of the efficacy of CBT in treating CFS found an effect size of d = 0.48 (95% CI 0.27–0.69).
In their letter, De Lange et al. (2008) refer to a review by Whiting et al. (2001) as part-evidence for their claim that CBT is effective for CFS. However, this review recommended the use of objective outcome measures e.g.
Outcomes such as ‘improvement,’ in which participants were asked to rate themselves as better or worse than they were before the intervention began, were frequently reported. However, the person may feel better able to cope with daily activities because they have reduced their expectations of what they should achieve, rather than because they have made any recovery as a result of the intervention. A more objective measure of the effect of any intervention would be whether participants have increased their working hours, returned to work or school, or increased their physical activities’.
Given one of the aims of CBT (for CFS) has been said to be ‘increased confidence in exercise and physical activity’ (O’Dowd et al.), we cannot have complete confidence that the improvements recorded in CBT trials thus far represent objective improvements [such as improvements in grey matter volume (GMV)], rather than simply being due to altering how patients answer questionnaires. An INAMI report (2006) on the use of CBT (combined with GET) in over 600 CFS patients in Belgium found that while patients reported improvements on their fatigue scores, there was negligible change on the tests of exercise capacity and there was actually a worsening of their employment status (as measured by the amount of hours worked per week), both at the end of the intervention and at follow-up.
You can read the rest of this comment here: http://brain.oxfordjournals.org/content/132/7/e119.long
Source: Kindlon T. Change in grey matter volume cannot be assumed to be due to cognitive behavioural therapy. Brain. 2009 Jul;132(Pt 7):e119; author reply e120. doi: 10.1093/brain/awn358. Epub 2009 Jan 29. http://brain.oxfordjournals.org/content/132/7/e119.long (Full article)