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Pathways to Prevention (P2P) Program

Advancing the Research on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS)


Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a complex, multifaceted disorder characterized by extreme fatigue and a host of other symptoms that can worsen after physical or mental activity, but do not improve with rest. The onset of ME/CFS symptoms may be sudden or gradual, with no discernible attachment to a specific event or time. In addition to extreme fatigue, people with ME/CFS may also experience:

  • Widespread muscle and joint pain
  • Sore throat
  • Tender lymph nodes in the neck or armpit
  • Headaches
  • Sleep problems
  • Difficulty with short-term memory or concentration.

Effects of the illness can range from moderate to debilitating, and can substantially impact everyday functioning. Routine daily activities such as cooking meals, brushing teeth, and caring for children become difficult. Additionally, sensitivity to environmental factors (e.g., noise, light, chemicals) may force many individuals with ME/CFS into seclusion or withdrawal from society.

The U.S. Centers for Disease Control and Prevention (CDC) reports over 1 million adults with ME/CFS in the United States, and recent evidence has shown a higher prevalence in females compared to males. Certain racial/ethnic groups have also been found to be at an increased risk for ME/CFS; most notably Native American and African American populations. The economic burden of ME/CFS, including annual health care costs, is estimated to be between $1.9 billion and $7.2 billion.


There are many aspects of ME/CFS that are problematic:

  • Unclear underlying mechanisms
  • Little agreement among clinical and research professionals, as well as patient groups, regarding the name of the illness
  • No laboratory tests for diagnosing ME/CFS, and its diagnosis is one of exclusion
  • No U.S. Food and Drug Administration-approved drugs or therapies
  • Disagreement among medical professionals on many aspects of ME/CFS, including whether the illness is real; and no definitive answer about the effectiveness of current therapies.

Workshop Goals

The workshop sought to clarify:

  • How the research on ME/CFS using multiple case definitions has contributed to the state of the current scientific literature on diagnosis, pathophysiology, treatment, cure, and prevention of ME/CFS
  • How the measurement outcomes (tools and measures) currently used by researchers of ME/CFS are able to distinguish among those patients diagnosed with ME/CFS, including the sensitivity of the tools and measures to identify subsets of patients according to duration, severity, nature of the illness, onset characteristics, and other categorizations
  • How the research on treatments or therapies shown to be effective in addressing symptoms of ME/CFS will lead to an understanding of the underlying pathology associated with ME/CFS
  • How innovative research approaches have provided an understanding of the pathophysiology of ME/CFS, and how this knowledge can be applied to the development of effective and safe treatments.

Sponsoring NIH Institutes, Centers, and Offices

The workshop was co-sponsored by: