Manu, P, Lane, T J, Matthews, D A · Ciba Foundation symposium · 1993 · DOI
This study looked at 405 patients who came to a hospital complaining of chronic fatigue and tried to figure out what was causing it. Doctors found that most patients had psychiatric conditions like depression or anxiety rather than physical diseases. About 30% of patients met the definition for ME/CFS, and these patients were more likely to attribute their illness to a viral infection than other fatigued patients.
This study is historically important because it represents a major perspective in ME/CFS research from the 1990s that emphasized psychiatric explanations for the condition. Understanding this viewpoint—and its limitations—helps patients and researchers recognize how diagnostic approaches have evolved and why more recent biological research has challenged these conclusions.
This study does not prove that ME/CFS is caused by psychiatric illness; it documents psychiatric comorbidity, which is common in many chronic diseases but does not establish causation. The study's cross-sectional design cannot determine whether psychiatric conditions preceded fatigue onset or developed as a consequence of chronic illness. The high reliance on psychiatric diagnosis in the analysis does not rule out underlying biological abnormalities in ME/CFS.
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
Manu, P, Lane, T J, & Matthews, D A (1993). Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification.. Ciba Foundation symposium. https://doi.org/10.1002/9780470514382.ch3
BibTeX
@article{mecfsatlas-manu-1993-chronic-fatigue,
author = {Manu, P and Lane, T J and Matthews, D A},
title = {Chronic fatigue and chronic fatigue syndrome: clinical epidemiology and aetiological classification.},
journal = {Ciba Foundation symposium},
year = {1993},
doi = {10.1002/9780470514382.ch3},
note = {PubMed: 8491100},
url = {https://www.mecfsatlas.com/evidence/manu-1993-chronic-fatigue},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-27. https://www.mecfsatlas.com/evidence/manu-1993-chronic-fatigue
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