Kalfas, Michail, Smakowski, Abigail, Hirsch, Colette et al. · Behavior therapy · 2022 · DOI
This study looked at worry in nearly 500 people with ME/CFS who received a talking therapy called cognitive behavioral therapy (CBT). About 7 in 10 patients had significant worry alongside their fatigue. After CBT, patients reported notably less worry, and this improvement stayed stable months later. People who worried severely at the start also experienced worse fatigue and had more difficulty with work and social activities.
This study highlights a frequently overlooked comorbidity—generalized worry—in ME/CFS patients and demonstrates that CBT-based worry reduction can produce meaningful, sustained improvements. Understanding worry's role in fatigue severity and functional impairment may help clinicians tailor treatment strategies to address both conditions simultaneously, potentially improving overall patient outcomes.
This study does not establish that worry *causes* ME/CFS or that treating worry will cure fatigue; the relationship may be bidirectional or influenced by shared biological factors. Without a control group, we cannot definitively conclude that CBT itself caused the improvements rather than other factors like natural recovery or supportive care. The findings apply specifically to patients accessing specialist secondary care and may not generalize to all ME/CFS 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
Kalfas, Michail, Smakowski, Abigail, Hirsch, Colette, Simiao, Fabio, & Chalder, Trudie (2022). Generalized Worry in Patients With Chronic Fatigue Syndrome Following Cognitive Behavioral Therapy: A Prospective Cohort Study in Secondary Care.. Behavior therapy. https://doi.org/10.1016/j.beth.2022.01.004
BibTeX
@article{mecfsatlas-kalfas-2022-generalized-worry,
author = {Kalfas, Michail and Smakowski, Abigail and Hirsch, Colette and Simiao, Fabio and Chalder, Trudie},
title = {Generalized Worry in Patients With Chronic Fatigue Syndrome Following Cognitive Behavioral Therapy: A Prospective Cohort Study in Secondary Care.},
journal = {Behavior therapy},
year = {2022},
doi = {10.1016/j.beth.2022.01.004},
note = {PubMed: 35987542},
url = {https://www.mecfsatlas.com/evidence/kalfas-2022-generalized-worry},
}Atlas snapshot reference
ME/CFS Atlas. Generator v1 / Scanner v1.4 / policy v0.1. Accessed 2026-05-28. https://www.mecfsatlas.com/evidence/kalfas-2022-generalized-worry
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