E2 ModerateModerate confidencePEM not requiredCase-ControlPeer-reviewedReviewed
Associations of physical and psychiatric conditions with chronic fatigue syndrome in Germany: an exploratory case-control study.
Jacob, Louis, Haro, Josep Maria, Kostev, Karel · Psychological medicine · 2022 · DOI
Quick Summary
Researchers in Germany studied nearly 20,000 adults to see which health conditions are linked to developing ME/CFS. They compared people newly diagnosed with ME/CFS to similar people without it, looking at health problems they had in the year before diagnosis. They found that cancer, sleep disorders, and depression were the conditions most strongly associated with ME/CFS.
Why It Matters
This study is one of the first to systematically examine how common physical and psychiatric conditions relate to ME/CFS risk. Understanding these associations may help clinicians recognize patients at higher risk and could point toward shared biological mechanisms underlying ME/CFS development.
Observed Findings
- Cancer, sleep disorders, and depression showed the strongest associations with ME/CFS diagnosis.
- Seven physical and psychiatric conditions were significantly associated with ME/CFS in the adjusted model.
- The study included 9,896 ME/CFS cases and 9,896 matched controls with a mean age of 49.5 years and 65.1% women.
- Conditions were selected for analysis only if present in at least 3% of the ME/CFS patient population.
Inferred Conclusions
- Multiple physical and psychiatric conditions are associated with ME/CFS, with sleep disorders and depression showing particularly strong links.
- These associations suggest potential shared biological or pathophysiological mechanisms warranting further investigation.
- The need for additional mechanistic studies to clarify the relationships between these conditions and ME/CFS.
Remaining Questions
- Do these conditions play a causal role in ME/CFS development, or are they early manifestations of undiagnosed ME/CFS?
- What are the underlying biological mechanisms linking cancer, sleep dysfunction, depression, and ME/CFS?
- How do these findings differ across populations outside Germany, and can they be replicated in other healthcare systems?
What This Study Does Not Prove
This study shows correlation, not causation—it does not prove that cancer, sleep disorders, or depression cause ME/CFS or vice versa. The temporal relationship (conditions documented one year before diagnosis) does not establish whether these conditions increase ME/CFS risk, result from early ME/CFS symptoms, or share a common underlying cause. Findings are based on diagnoses recorded in primary care and may not capture all relevant conditions.
Tags
Symptom:Unrefreshing SleepFatigue
Method Flag:Weak Case DefinitionExploratory Only
Metadata
- DOI
- 10.1017/S0033291720002470
- PMID
- 32686638
- Review status
- Editor reviewed
- Evidence level
- Single-study or moderate support from human research
- Last updated
- 12 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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