E0 ConsensusModerate confidencePEM unclearSystematic-ReviewPeer-reviewedMachine draft
Sympathetic nervous system dysfunction in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis: a review of case-control studies.
Martínez-Martínez, Laura-Aline, Mora, Tania, Vargas, Angélica et al. · Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases · 2014 · DOI
Quick Summary
This review examined whether ME/CFS, fibromyalgia, IBS, and interstitial cystitis share a common problem: an overactive stress-response system in the nervous system. Researchers looked at 196 published studies that compared patients with these conditions to healthy controls. They found that about 65% of studies showed these patients have a nervous system stuck in 'overdrive,' which could explain why these conditions often occur together.
Why It Matters
This systematic review provides evidence that ME/CFS shares a common autonomic nervous system dysfunction with other medically-recognized conditions, supporting the biological basis of the disease. Understanding that sympathetic overdrive is widespread across these syndromes may guide the development of targeted treatments aimed at restoring nervous system balance rather than simply managing individual symptoms.
Observed Findings
- 65% of included case-control studies reported sympathetic nervous system predominance in fibromyalgia, ME/CFS, IBS, and interstitial cystitis
- 7% of studies found parasympathetic predominance in these syndromes
- The most common assessment methods were heart rate variability analysis, sympathetic skin response, tilt table testing, and genetic studies
- These four clinically overlapping syndromes shared a common pattern of autonomic dysfunction across 196 published comparative studies
Inferred Conclusions
- Sympathetic nervous system dysfunction is a common feature across fibromyalgia, ME/CFS, IBS, and interstitial cystitis, suggesting it may represent a shared underlying pathogenic mechanism
- The recognition of sympathetic predominance in these four syndromes supports dysautonomia as a potential unifying explanation for their clinical overlap and coexistence
- Therapies targeting autonomic rebalancing—both pharmacological and non-pharmacological—warrant investigation as potential treatments for these conditions
Remaining Questions
- Is sympathetic dysfunction the primary cause of these syndromes, or a secondary consequence of chronic illness?
- Which specific measurements of sympathetic function are most clinically relevant and reproducible across studies?
What This Study Does Not Prove
This review does not establish that sympathetic dysfunction *causes* these conditions—only that it is frequently observed in them (correlation, not causation). It also does not identify which specific sympathetic abnormalities are primary versus secondary, nor does it determine whether correcting sympathetic dysfunction would improve clinical outcomes. The heterogeneity of measurement methods across studies limits the ability to draw firm quantitative conclusions.
Tags
Symptom:Orthostatic IntolerancePainFatigue
Biomarker:Blood Biomarker
Method Flag:PEM Not DefinedWeak Case Definition
Metadata
- DOI
- 10.1097/RHU.0000000000000089
- PMID
- 24662556
- Review status
- Machine draft
- Evidence level
- Established evidence from major reviews, guidelines, or evidence maps
- Last updated
- 8 April 2026
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 →
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