Williams, T E, Chalder, T, Sharpe, M et al. · Psychological medicine · 2017 · DOI
This study found that ME/CFS is not one single condition but rather five distinct subtypes that affect people differently. Researchers analyzed data from 541 patients and identified groups characterized by: low overall symptoms, mood disorders, overlapping conditions like fibromyalgia, combined multiple symptoms, or avoidance behaviors with fear of activity. Understanding these differences could help doctors tailor treatments to what works best for each person's specific type.
This research demonstrates that ME/CFS is heterogeneous, meaning patients have different symptom patterns and presentations. By identifying distinct subtypes, the study suggests that future treatments could be more personalized and effective, and that research into causes may need to examine different mechanisms for different subgroups rather than assuming all ME/CFS has the same etiology.
This study does not establish what causes ME/CFS or why these subgroups exist—it only describes patterns observed in one trial population. The findings are correlational, not causal, and may not generalize to all ME/CFS patients, particularly those with different severities or those who did not participate in the PACE trial. The cross-sectional design cannot determine whether these subgroups remain stable over time or represent disease progression stages.
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
Williams, T E, Chalder, T, Sharpe, M, & White, P D (2017). Heterogeneity in chronic fatigue syndrome - empirically defined subgroups from the PACE trial.. Psychological medicine. https://doi.org/10.1017/S0033291716003615
BibTeX
@article{mecfsatlas-williams-2017-heterogeneity-chronic,
author = {Williams, T E and Chalder, T and Sharpe, M and White, P D},
title = {Heterogeneity in chronic fatigue syndrome - empirically defined subgroups from the PACE trial.},
journal = {Psychological medicine},
year = {2017},
doi = {10.1017/S0033291716003615},
note = {PubMed: 28112075},
url = {https://www.mecfsatlas.com/evidence/williams-2017-heterogeneity-chronic},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-29. https://www.mecfsatlas.com/evidence/williams-2017-heterogeneity-chronic
Contribute
Private, reviewed by a human. Not a public comment thread.