Fibromyalgia and chronic fatigue syndrome: similarities and differences.
Buchwald, D · Rheumatic diseases clinics of North America · 1996 · DOI
Quick Summary
This review compared ME/CFS and fibromyalgia (FM), two conditions that cause fatigue, muscle pain, and sleep problems. The researchers found that these two illnesses are very similar in their symptoms and how they affect people's lives, even though doctors use different criteria to diagnose them. Some patients have both conditions at the same time, which makes their suffering worse.
Why It Matters
Understanding the similarities and differences between ME/CFS and fibromyalgia helps patients and clinicians recognize when both conditions may be present, potentially improving diagnosis and treatment planning. This work supports the recognition of overlapping syndromes and may guide future research into shared biological mechanisms and targeted interventions for patient subgroups.
Observed Findings
ME/CFS and FM show remarkable similarity in demographic characteristics and clinical presentations
Few differences exist across symptom domains, examination findings, and laboratory test results
Few differences observed in functional status, psychosocial features, and associated psychiatric disorders
Fibromyalgia appears to represent an additional burden of suffering when concurrent with ME/CFS
Neither condition has widely accepted diagnostic studies or pathogenic explanatory models
Inferred Conclusions
ME/CFS and FM are substantially similar clinical syndromes despite different diagnostic criteria
Concurrent ME/CFS and FM is clinically important to recognize due to increased disease burden
Clarifying similarities and differences between these conditions may help identify patient subsets for targeted therapeutic interventions
Improved understanding of the relationship between these syndromes could advance prognosis studies
Remaining Questions
What are the underlying biological mechanisms that cause the symptom overlap between ME/CFS and FM?
What This Study Does Not Prove
This review does not establish whether ME/CFS and FM share a common underlying cause or are distinct diseases that frequently co-occur. It does not identify specific biomarkers or diagnostic tests that can reliably distinguish the two conditions or explain their pathogenic mechanisms. The review also cannot determine which specific treatments work best for each condition or their combination.
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 →