Reducing fears that exercise or activity will make symptoms worse is one of the most important factors determining the success of cognitive behaviour therapy (CBT) or graded exercise therapy (GET) in reducing fatigue and improving physical function in people with chronic fatigue syndrome (CFS), according to new analysis of data from the PACE trial, reported in The Lancet Psychiatry journal.
CFS (sometimes referred to as myalgic encephalomyelitis, ME) is a condition for which one of the defining symptoms is exhaustion, affecting a person's everyday life to varying degrees of severity. It is thought to affect around 250000 people in the UK . Existing treatments for CFS aim to reduce fatigue (exhaustion) and improve physical function (such as an improving a patient's ability to walk, or to do everyday tasks which most people take for granted).
The PACE trial, published in The Lancet in 2011 , examined the effects of three different treatments for people with CFS, compared with usual specialist medical care (SMC): cognitive behaviour therapy (CBT, where a health professional helps the patient to understand and change the way they think about and respond to their symptoms), graded exercise therapy (GET, a personalised and gradually increasing exercise programme delivered by a physiotherapist), and adaptive pacing therapy (APT, where patients adapt activity levels to the amount of energy they have). The study found that people with CFS benefitted from CBT or GET more than from APT or SMC.
In this study, led by Professor Trudie Chalder, from Kings College London, UK, researchers from King's College London, Oxford University, and Queen Mary University of London, UK, used a statistical method called mediation analysis to identify the factors, such as beliefs about activity and physical fitness through which CBT and GET had their beneficial effects on fatigue and physical function . These potential mediating factors were almost all measured halfway through the study participants' receipt of treatment.
According to Professor Chalder, "Although the PACE trial results suggest that CBT and GET offer safe and effective treatment options for a majority of CFS patients, the improvements seen in the trial were moderate. By identifying the mechanisms whereby some patients benefit from treatment, we hope that this will allow treatments to be developed, improved, or optimised."
Of all the mediating factors analysed, the researchers found that a reduction in fear avoidance beliefs (fears that exercise or activity will make symptoms worse, which is an understandable reaction to having CFS) was the strongest, accounting for up to 60% of the overall effect of CBT and GET on outcomes. Fear avoidance improved more with GET than with CBT, and improved exercise tolerance (as measured by metres walked in a fixed time) was a strong mediator of GET alone. Other factors analysed (including avoidance of activity, damage beliefs and catastrophizing) were weaker mediators of the effects on fatigue and physical function.
According to Professor Chalder, "Our results suggest that fearful beliefs can be changed by directly challenging such beliefs (as in CBT) or by simple behaviour change with a graded approach to the avoided activity (as in GET). Clinically, the results suggest that therapists delivering CBT could encourage more physical activities such as walking, which might enhance the effect of CBT and could be more acceptable to patients."
One of the study co-authors, Professor Peter White, from Queen Mary, University of London, UK, added, "It is important to bear in mind that this paper addresses how CBT and GET work for CFS. It does not speak to how CFS arises in the first place."
In a linked Comment, Dr Hans Knoop and Jan Wiborg from Radboud University Medical Centre, the Netherlands, write that, "Chalder and colleagues conclude that future studies should focus on improving self-efficacy and increasing physical activity because these identified mediators had strong relations with the outcomes. We tend to draw a different conclusion with respect to the potential of improving outcome by increasing physical activity. We assume that an increase in physical activity is nothing more than a catalyst for the change in cognitions about activity and symptoms in patients with chronic fatigue syndrome. Future studies should focus on how these beliefs can be changed more rapidly and effectively. In our own protocol, we ask patients to gradually increase physical activity and present it as a way to increase your ability to become active. Once a patient is convinced that this is possible, irrespective of the actual level of activity, an important step towards recovery is taken."
NOTES TO EDITORS:
The study was funded by UK Medical Research Council, Department of Health for England, Scottish Chief Scientist Office, Department for Work and Pensions, National Institute for Health Research (NIHR), NIHR Biomedical Research Centre for Mental Health at South London, and Maudsley NHS Foundation Trust and King's College London. This press release is based on independent research arising in part from a Doctoral Research Fellowship supported by the National Institute for Health Research.
 The mediating factors analysed were: catastrophizing; avoidance behaviour; symptom focusing; all-or-nothing behaviour; embarrassment avoidance; fear avoidance; damage beliefs; self-efficacy; HADS depression; HADS anxiety; Jenkins sleep scale; fitness; Borg scale; distance walked
The Lancet Psychiatry