Schmaling, Karen B, Betterton, Karran L · Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation · 2016 · DOI
This study followed 93 patients with ME/CFS over 18 months to understand how cognitive problems (like memory and perception difficulties) and physical function change over time. Patients who had both ME/CFS and fibromyalgia reported more pain, worse physical function, and more cognitive difficulties than those with ME/CFS alone. Interestingly, pain improved over time only for the ME/CFS-only group, suggesting that having both conditions may make recovery slower and more complicated.
This study provides longitudinal evidence that ME/CFS patients with comorbid fibromyalgia represent a more severely disabled subgroup with distinct cognitive profiles and slower improvement trajectories. Understanding these differences is critical for clinicians tailoring treatment approaches and for researchers investigating whether cognitive dysfunction warrants inclusion in diagnostic criteria.
This study does not establish the mechanism causing cognitive difficulties in ME/CFS or whether cognitive deficits are primary neurological features or secondary to pain and fatigue. It also cannot prove causation between cognitive problems and functional decline, only correlation, and results may not generalize beyond tertiary care 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
Schmaling, Karen B & Betterton, Karran L (2016). Neurocognitive complaints and functional status among patients with chronic fatigue syndrome and fibromyalgia.. Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation. https://doi.org/10.1007/s11136-015-1160-y
BibTeX
@article{mecfsatlas-schmaling-2016-neurocognitive-complaints,
author = {Schmaling, Karen B and Betterton, Karran L},
title = {Neurocognitive complaints and functional status among patients with chronic fatigue syndrome and fibromyalgia.},
journal = {Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation},
year = {2016},
doi = {10.1007/s11136-015-1160-y},
note = {PubMed: 26471263},
url = {https://www.mecfsatlas.com/evidence/schmaling-2016-neurocognitive-complaints},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/schmaling-2016-neurocognitive-complaints
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