Deale, A, Chalder, T, Wessely, S · Journal of psychosomatic research · 1998 · DOI
This study examined whether what ME/CFS patients believe about the cause of their illness affects how well they recover with treatment. Researchers found that patients' beliefs about whether their condition was physical didn't predict treatment success. However, patients who changed their views about avoiding exercise and activity—and actually started doing more—improved more with cognitive-behavior therapy than with relaxation alone.
This study challenges the assumption that correcting patients' physical illness beliefs is necessary for treatment success in ME/CFS. Instead, it suggests that helping patients gradually increase activity and modify avoidance behaviors—regardless of what they believe caused their illness—may be the key mechanism for improvement, potentially making psychological treatments more acceptable and effective.
This study does not prove that illness beliefs are unimportant in all ME/CFS patients or treatment contexts—findings are specific to CBT versus relaxation in this small sample. The study measures association, not causation, so we cannot confirm that changing avoidance beliefs directly causes improvement rather than both occurring together. Results may not generalize to other treatment types or patient populations.
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
Deale, A, Chalder, T, & Wessely, S (1998). Illness beliefs and treatment outcome in chronic fatigue syndrome.. Journal of psychosomatic research. https://doi.org/10.1016/s0022-3999(98)00021-x
BibTeX
@article{mecfsatlas-deale-1998-illness-beliefs,
author = {Deale, A and Chalder, T and Wessely, S},
title = {Illness beliefs and treatment outcome in chronic fatigue syndrome.},
journal = {Journal of psychosomatic research},
year = {1998},
doi = {10.1016/s0022-3999(98)00021-x},
note = {PubMed: 9720857},
url = {https://www.mecfsatlas.com/evidence/deale-1998-illness-beliefs},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/deale-1998-illness-beliefs
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