The DePaul Symptom Questionnaire-2: A Validation Study.
Bedree, Helen, Sunnquist, Madison, Jason, Leonard A · Fatigue : biomedicine, health & behavior · 2019 · DOI
Quick Summary
Researchers improved a questionnaire called the DSQ-2 that helps doctors identify and understand ME/CFS by asking patients about their specific symptoms. They tested this updated questionnaire with 399 people who have ME or CFS and found that it works well at measuring the main symptoms of these illnesses, including post-exertional malaise (feeling worse after activity), brain fog, pain, and sleep problems. The questionnaire is now a more reliable tool for both diagnosing ME/CFS and understanding how the illness affects different people.
Why It Matters
Having a reliable, validated questionnaire is crucial for ensuring ME/CFS patients are accurately diagnosed and their symptoms are properly documented in clinical and research settings. This improved tool can help standardize how doctors and researchers assess ME/CFS, making it easier to identify patients, track symptom changes, and ensure consistency across studies and clinical practice.
Observed Findings
The DSQ-2 identified eight distinct symptom factors with strong internal consistency (Cronbach's alphas ranging from .73 to .91).
Post-exertional malaise, cognitive impairment, fever/flu symptoms, pain, sleep disruption, orthostatic intolerance, genitourinary issues, and temperature intolerance emerged as separate measurable dimensions of ME/CFS.
The revised and new items in the DSQ-2 improved the questionnaire's ability to assess symptom domains and evaluate compliance with recent ME/CFS case definitions.
The study population of 399 adults with ME/CFS provided sufficient data for exploratory factor analysis.
Inferred Conclusions
The DSQ-2 is a more thorough and precise instrument for assessing ME/CFS symptomatology compared to its predecessor.
The eight-factor structure supports the multidimensional nature of ME/CFS and validates that these symptom domains are distinct and measurable.
The improved psychometric properties of the DSQ-2 make it suitable for both clinical assessment and research evaluation of case definition fulfillment.
Remaining Questions
How does the DSQ-2 perform with diverse populations, including different ages, ethnic backgrounds, and disease severity levels?
What is the test-retest reliability of the DSQ-2, and do symptom factor scores remain stable over time?
What This Study Does Not Prove
This study validates that the DSQ-2 reliably measures symptoms—it does not prove what causes ME/CFS or how to treat it. The questionnaire's ability to measure symptoms also does not establish that everyone with these symptoms has ME/CFS, as other conditions may produce similar presentations. Additionally, this cross-sectional validation does not determine whether symptoms remain stable over time or how they change with different treatments.