Chalder, Trudie, Goldsmith, Kimberley A, White, Peter D et al. · The lancet. Psychiatry · 2015 · DOI
This study examined how cognitive behaviour therapy (CBT) and graded exercise therapy (GET) help reduce fatigue and improve physical function in ME/CFS patients. The researchers found that both treatments work partly by changing how afraid patients are of activity and what they believe about their illness, and that GET also works by gradually building exercise tolerance. The study suggests that changing unhelpful thoughts and gradually increasing activity are important parts of recovery for some patients.
Understanding *how* treatments work is crucial for personalizing care and improving outcomes in ME/CFS. This study identifies specific psychological and behavioral mechanisms—fear avoidance and exercise tolerance—that may be targets for therapy, helping clinicians tailor interventions and helping patients understand what aspects of treatment are most beneficial for them.
This mediation analysis does not establish that fear avoidance beliefs or low exercise tolerance are the *primary cause* of ME/CFS; it only shows they may be factors that treatments target. The study does not prove these treatments are universally safe or effective for all ME/CFS patients, nor does it address post-exertional malaise (PEM) as a distinct outcome. Correlation between changes in beliefs/behavior and symptom improvement does not prove a causal mechanism.
About the PEM badge: “PEM required” means post-exertional malaise was an explicit required diagnostic criterion for participant inclusion in this study — not that PEM was studied, observed, or discussed. Studies using criteria that do not require PEM (e.g. Fukuda, Oxford) are tagged “PEM not required”. How the atlas works →
The first block is for the primary paper and is the citation you should use in research work. The atlas-snapshot line only applies if you are specifically referring to this atlas’s reading of the paper on the date shown.
Primary citation
Chalder, Trudie, Goldsmith, Kimberley A, White, Peter D, Sharpe, Michael, & Pickles, Andrew R (2015). Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial.. The lancet. Psychiatry. https://doi.org/10.1016/S2215-0366(14)00069-8
BibTeX
@article{mecfsatlas-chalder-2015-rehabilitative-therapies,
author = {Chalder, Trudie and Goldsmith, Kimberley A and White, Peter D and Sharpe, Michael and Pickles, Andrew R},
title = {Rehabilitative therapies for chronic fatigue syndrome: a secondary mediation analysis of the PACE trial.},
journal = {The lancet. Psychiatry},
year = {2015},
doi = {10.1016/S2215-0366(14)00069-8},
note = {PubMed: 26359750},
url = {https://www.mecfsatlas.com/evidence/chalder-2015-rehabilitative-therapies},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/chalder-2015-rehabilitative-therapies
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