Interpretation bias modification (CBM-I) for fatigue in long term health conditions - A feasibility study.
Hughes, Alicia, Tyson, Gabriella, Moss-Morris, Rona et al. · Behaviour research and therapy · 2026 · DOI
Quick Summary
This study tested a new online training program designed to help people with long-term illnesses (including ME/CFS and long COVID) reduce fatigue by changing how they interpret ambiguous situations. People in the study completed 12 online training sessions and were tracked for four months. The training was popular with participants, most people completed it, and it showed promise in reducing fatigue and low mood.
Why It Matters
ME/CFS patients often experience profound fatigue and mood difficulties with limited evidence-based treatment options. This study suggests a brief, accessible digital intervention targeting cognitive biases may help reduce fatigue across multiple long-term conditions including ME/CFS, offering a scalable, low-burden approach that could complement existing management strategies.
Observed Findings
77% of participants completed the full 12-session CBM-I dose, indicating good adherence to the online intervention.
70% of participants were retained at the four-month follow-up assessment.
The intervention produced a large effect size (g=0.834) on fatigue-related interpretation bias, the theorised mechanism of change.
Small effect sizes were observed for self-reported fatigue and depression outcomes, but not for anxiety.
Participants rated the CBM-I training as acceptable, supporting feasibility for future full-scale trials.
Inferred Conclusions
Fatigue-focused CBM-I is acceptable and feasible to deliver in people with long-term health conditions including ME/CFS.
CBM-I successfully targets interpretation bias, supporting the theoretical model underlying the intervention.
A full-scale randomised controlled trial of CBM-I for fatigue in long-term conditions is justified by these preliminary findings.
Digital CBM-I may represent a brief, easy-to-administer intervention option for fatigue management in long-term illness populations.
Remaining Questions
Does CBM-I produce clinically meaningful reductions in fatigue severity in ME/CFS specifically, or only in mixed long-term condition samples?
What This Study Does Not Prove
This feasibility study does not establish that CBM-I is effective for treating ME/CFS fatigue—it demonstrates only that a full trial is logistically feasible and that the intervention shows promise. The study was not powered to detect clinically meaningful differences in fatigue outcomes, and findings in mixed long-term conditions may not translate specifically to ME/CFS populations. Small effect sizes on fatigue and depression suggest effect magnitude remains uncertain pending larger trials.
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 →