White and colleagues conclude from the results of the PACE trial that ‘recovery from CFS (chronic fatigue syndrome) is possible, and that CBT (cognitive behavioural therapy) and GET (graded exercise therapy) are the therapies most likely to lead to recovery’ (White et al. Reference White, Goldsmith, Johnson, Chalder and Sharpe2013).

However, in the body of the text, they qualify their use of the term ‘recovery’. Citing Nisenbaum et al. (Reference Nisenbaum, Jones, Unger, Reyes and Reeves2003) they write, ‘recovery may be taken to imply that the patient has made a transition from ill health to remission and also is at little risk of recurrence’ but then acknowledge that, in the absence of longitudinal data, it is not possible to discriminate between remission and recovery in CFS.

Thus, in the current paper, ‘recovery’ does not mean recovery as understood by Nisenbaum but ‘recovery from the current episode of the illness’, a state described by Nisenbaum as ‘remission’.

This difference is important because CFS is known to pursue ‘a fluctuating course with periods of relative remission and relapse’ (CFS/ME Working Group, 2002) and Cochrane reviews of CBT (Price et al. Reference Price, Mitchell, Tidy and Hunot2008) and GET (Edmonds et al. Reference Edmonds, McGuire and Price2004) have reported inconsistent findings at long-term follow-up, with some studies showing that initial gains can diminish with time. Writing about the PACE trial, Edmonds et al. concluded ‘Even when the results of that study are available, it is possible that uncertainty will remain. Further randomized studies are needed, with longer follow-up, to determine whether patients who respond to exercise stay well or relapse.’