Short, Keryn, McCabe, Marita, Tooley, Greg · Journal of psychosomatic research · 2002 · DOI
This study tested whether people with ME/CFS have actual problems with memory and thinking skills, or whether the difficulty they experience is mainly related to depression, anxiety, or fatigue. Researchers compared 23 people with ME/CFS to 23 healthy people using both objective tests (like memory tasks) and subjective reports (how people felt their thinking was affected). The findings showed that on actual cognitive tests, people with ME/CFS performed just as well as healthy controls, though they reported feeling that their thinking was worse.
This study addresses 'brain fog'—one of ME/CFS patients' most concerning symptoms—by distinguishing between perceived and measurable cognitive problems. Understanding that psychological factors like depression only partially explain cognitive complaints supports the view that 'brain fog' in ME/CFS involves unique neurological mechanisms beyond mood disorders, potentially validating patients' experiences and guiding treatment approaches.
This study does not prove that cognitive complaints in ME/CFS are purely subjective or 'all in the head.' It also cannot establish causation—the study's cross-sectional design cannot determine whether fatigue causes cognitive perception changes or vice versa. The small sample size (23 per group) and 2002 publication date mean findings may not generalize to all ME/CFS populations or reflect current understanding of neuroinflammatory mechanisms.
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
Short, Keryn, McCabe, Marita, & Tooley, Greg (2002). Cognitive functioning in chronic fatigue syndrome and the role of depression, anxiety, and fatigue.. Journal of psychosomatic research. https://doi.org/10.1016/s0022-3999(02)00290-8
BibTeX
@article{mecfsatlas-short-2002-cognitive-functioning,
author = {Short, Keryn and McCabe, Marita and Tooley, Greg},
title = {Cognitive functioning in chronic fatigue syndrome and the role of depression, anxiety, and fatigue.},
journal = {Journal of psychosomatic research},
year = {2002},
doi = {10.1016/s0022-3999(02)00290-8},
note = {PubMed: 12069872},
url = {https://www.mecfsatlas.com/evidence/short-2002-cognitive-functioning},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-30. https://www.mecfsatlas.com/evidence/short-2002-cognitive-functioning
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