Nacul, Luis, Lacerda, Eliana M, Kingdon, Caroline C et al. · Journal of health psychology · 2019 · DOI
This study examines why ME/CFS research has been inconsistent and controversial. The main problem is that doctors and researchers use different definitions to diagnose ME/CFS, which means different groups of patients are studied in different research projects. The authors explain how using clearer, more consistent diagnostic criteria could help researchers better understand the disease and make progress in finding treatments.
This study addresses a fundamental obstacle to ME/CFS research progress: the lack of diagnostic consensus. By clarifying how diagnostic inconsistency introduces bias and reduces study validity, it provides evidence-based guidance for standardizing case definitions, which could accelerate discovery of biomarkers, underlying mechanisms, and effective treatments.
This review does not prove which specific case definition is correct or superior, nor does it test diagnostic criteria against biological markers. It does not establish causation or present new empirical data about ME/CFS pathophysiology—it is a conceptual analysis of methodological problems in existing literature.
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
Nacul, Luis, Lacerda, Eliana M, Kingdon, Caroline C, Curran, Hayley, & Bowman, Erinna W (2019). How have selection bias and disease misclassification undermined the validity of myalgic encephalomyelitis/chronic fatigue syndrome studies?. Journal of health psychology. https://doi.org/10.1177/1359105317695803
BibTeX
@article{mecfsatlas-nacul-2019-how-have,
author = {Nacul, Luis and Lacerda, Eliana M and Kingdon, Caroline C and Curran, Hayley and Bowman, Erinna W},
title = {How have selection bias and disease misclassification undermined the validity of myalgic encephalomyelitis/chronic fatigue syndrome studies?},
journal = {Journal of health psychology},
year = {2019},
doi = {10.1177/1359105317695803},
note = {PubMed: 28810428},
url = {https://www.mecfsatlas.com/evidence/nacul-2019-how-have},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-25. https://www.mecfsatlas.com/evidence/nacul-2019-how-have
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