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Dr. Leonard Jason's Research Team

"Researchers and clinicians need to be aware of the strong sentiments that patients have
for [the name, definition and classification of] Myalgic Encephalomyelitis, which is historically correct (Ramsay, 1981) and has been used internationally (Hyde, Goldstein, & Levine, 1992)."
-Dr. Leonard Jason-

In recognition of his contribution to the ME and cfs community, Dr. Jason received the Dutch ME-Foundation International ME-Award for 2003 for outstanding work in the previous 10 years in the field of Myalgic Encephalomyelitis/chronic fatigue syndrome.  Dr. Jason is co-author of the Handbook of Chronic Fatigue Syndrome, and former Vice-President of the IACFS/ME, where he continues to serve on several committees.  He has also served many years on the CFS Advisory Committee at the US Department of Health & Human Services.

Dr. Jason's research group at DePaul University has been so prolific with their publications on ME/cfs that it would be impractical to list them all here. Instead, we've attempted to summarize Dr. Jason's contributions to ME/cfs research, particularly in the areas of name attribution, epidemiology, case definition and mortality studies. For more than a decade, Dr. Jason and his team at DePaul University’s Center for Community Research have worked to define the scope and impact of ME/cfs worldwide.  (See the complete reference list of articles and books by Dr. Jason's team at DePaul University.)

A summary of Dr. Jason's research in:
Name Attribution   -   Epidemiology   -   Case Definition Studies   -   Mortality

Name Attribution

Two studies explored whether alternative names for cfs (e.g., chronic fatigue syndrome, Myalgic Encephalopathy) do influence attributions by medical trainees, and college undergraduates regarding this syndrome. Participants were randomly assigned to two groups, with the difference between groups involving the type of diagnostic label given for a case description of a patient with prototypic symptoms of chronic fatigue syndrome. Results showed that participants' attributions about cfs varied on the basis of the different diagnostic labels used to characterize it. The Myalgic Encephalopathy label was associated with the poorest prognosis, and this term was more likely to be associated with a physiological rather than a psychological cause to the illness.

Many patient groups believe that changing the name from Myalgic Encephalomyelitis to cfs was thus a major contributing factor to the stigmatization of this illness.

Evaluating attributions for an illness based upon the name: Chronic fatigue syndrome, Myalgic Encephalopathy and Florence Nightingale Disease.  (Abstract) Jason, L.A., Taylor, R.R., Plioplys, S., Stepanek, Z., & Shlaes, J.(2002). American Journal of Community Psychology, 30,133-148. "All groups read the same case study of a person with classic symptoms of chronic fatigue syndrome."  "...findings indicated that the name, chronic fatigue syndrome, may be regarded less seriously than the Myalgic Encephalopathy name with respect to some important aspects of the illness."

Attitudes regarding chronic fatigue syndrome: The importance of a name.  (Abstract) Jason, L.A., Taylor, R.R., Stepanek, Z., & Plioplys, S. (2001)Journal of Health Psychology, 6, 61-71. "Participants prompted with the myalgic encephalopathy name were more likely to attribute a biomedical cause to the illness, and less likely to consider patients as candidates for organ donation than those prompted with the CFS name."


Dr. Jason found in the early 1990s that previous epidemiological studies derived their samples from physician referrals in hospital and community-based clinics. These studies under-represented low-income and under-served minorities, people who manifest higher levels of chronic illness while also being less likely to have access to the health care system — and who are thus less likely to be counted in prevalence rates derived from treatment sources.

These studies also underestimated the prevalence of ME/cfs in the general population because they depended on diagnoses by healthcare providers who discounted the existence of the illness and would thus fail to diagnose it.

In 1993, Jason and colleagues interviewed a random community-based sample of approximately 1,000 adults. Those individuals who self-reported having ME/cfs or many of the symptoms of ME/cfs were examined by a physician and interviewed by a psychiatrist in order to determine whether they met case criteria for ME/cfs. The research team's diagnosis of .2% (200 per 100,000) was over ten times higher than the rate originally reported by the CDC. In a larger study conducted from 1995 to 1998, Jason, Richman and colleagues screened a random sample of 18,675 individuals for ME/cfs symptomatology.

Approximately .42% of the sample was determined to have cfs, with rates being higher among Latino and African-American respondents when compared to White respondents. The results of this epidemiological study suggested that this illness may affect approximately 800,000 people in the United States. Women, Latinos, middle-aged individuals, and persons of middle to lower socioeconomic status were found to be at higher risk for this illness. The findings directly contradicted the perception that middle to upper-class Caucasian women were the primary individuals with this illness. Moreover, about 90% of people identified as having ME/cfs in this sample had not been previously diagnosed by a physician prior to participation in the study, which highlights the limitations of prior ME/cfs epidemiological studies based solely on samples recruited from hospitals or primary care providers.

A community-based study of chronic fatigue syndrome. Jason, L.A., Richman, J.A., Rademaker, A.W., Jordan, K.M., Plioplys, A.V., Taylor, R., et al. (1999). Archives of Internal Medicine. 159, 2129-2137.  "The highest levels of CFS were consistently found among women, minority groups, and persons with lower levels of education and occupational status.  Earlier findings suggesting that CFS is a syndrome primarily affecting white, middle-class patients were not supported by our findings."

Estimating rates of Chronic Fatigue Syndrome from a community based sample: A pilot study. (Abstract) Jason, L.A., Taylor, R.R., Wagner, L., Holden, J., Ferrari, J.R., Plioplys, A.V., Plioplys, S., Lipkin, D., & Papernik, M. (1995). American Journal of Community Psychology, 23, 557-568. "Different definitions of CFS were employed, and higher rates (0.2%) of CFS were found than in previous studies."

Case Definition Studies

Dr. Jason has been instrumental in refuting the unwarranted bias against the organic nature of this serious disease, Myalgic Encephalomyelitis/cfs. Considering the ineffectiveness of the Fukuda 1994 Case Definition in clarifying the disease in a clinical setting or identifying homogeneous patient cohorts for research, other efforts by Dr. Jason have been directed towards investigating the new Canadian Case Definition of ME/CFS, helping develop and validate a new pediatric case definition, conceptualizing subtypes, and exploring political issues related to this illness.

Problems with the New CDC CFS Prevalence Estimates
Leonard Jason, Ph.D., DePaul University

A Pediatric Case Definition for Myalgic Encephalomyelitis and Chronic Fatigue Syndrome. (2006) Journal of Chronic Fatigue Syndrome. Jason, L.A., Bell, D.S., Rowe, K., Van Hoof, E.L.S., Jordan, K., Lapp, C., Gurwitt, A., Miike, T., Torres-Harding, S., De Meirleir, K. & IACFS

Chronic fatigue syndrome: The need for subtypes.  Jason, L.A., Corradi, K., Torres-Harding, S., Taylor, R.R., & King, C. (2005).  Neuropsychology Review, 15, 29-58. "The current U.S. case definition for CFS (Fukuda et al., 1994) is characterized by vaguely worded criteria that lack operations definition and guidelines to assist health care professional in their interpretation and application of the diagnostic too. (Jason et al., 1999d).  The Canadian case definition [includes] these critical symptoms and use of such types of case definitions might aid in the selection of more homogeneous samples. Based on the research reviewed in this section, we would encourage researchers to compare and contrast categories of patients meeting the Canadian Case definition and the Fukuda et al. (1994) criteria.  In addition, the provision of standardized measures for assessment and scoring guidelines should reduce clinicians’ difficulty with the criteria and their need to modify the criteria in clinical practice. In effect, the use of standardized measures should reduce criterion variance and improve diagnostic reliability (King and Jason, 2004)."
(Abstract and summary only)

Comparing the Fukuda et al. criteria and the Canadian case definition for chronic fatigue syndrome.  Jason, L.A., Torres-Harding, S.R., Jurgens, A., & Helgerson, J. (2004).  Journal of Chronic Fatigue Syndrome, 12, 37-52.  "...those individuals in this study meeting the Canadian criteria appear to have more symptoms, more physical functional impairment, and less psychopathology than those in the CF-psychiatric group.  In addition, the Canadian criteria identifies patients with more fatigue/weakness, neurological and neuropsychiatric symptoms than the Fukuda CFS criteria does."

Politics, science, and the emergence of a new disease: The case of Chronic Fatigue Syndrome. (Abstract) Jason, L.A., Richman, J.A., Friedberg, F., Wagner, L., Taylor, R., & Jordan, K.M. (1997).  American Psychologist, 52, 973-983.  "Many physicians minimized the seriousness of this disorder and also interpreted the syndrome as being equivalent to a psychiatric disorder. These attitudes had negative consequences for the treatment of CFS.  However, the use of the revised CFS case definition might have produced heterogeneous patient groups, possibly including some patients with pure psychiatric disorders."


Dr. Jason's team did an analysis of the National CFIDS Foundation's ME/cfs patient Memorial List.  This article presents their findings.

Causes of Death among Patients with Chronic Fatigue Syndrome  Leonard A. Jason, Karina Corradi, Sara Gress, Sarah Williams and Susan Torres-Harding DePaul University (2006). "The three most prevalent causes of death were heart failure, suicide, and cancer, which accounted for 59.6% of all deaths. The mean age of those who died from cancer and suicide was 47.8 and 39.3 years, respectively [and heart failure, 58.7], which is considerably younger than those who died from cancer and suicide in the general population.  For each of these areas, there is supportive evidence that might help explain why heart failure, cancer, and suicide might be associated with deaths among people with CFS in this sample.  The implications of these findings are discussed."


Research Categories

Research Overview
Contribute to Research
DePaul Univ/Jason
Oxidative Stress

The Center for Community Research at DePaul University

DePaul ME and cfs Mortality Study Recruitment
"You are invited to participate in this study because you knew an individual who was diagnosed with ME or CFS and has since passed away. We are looking to document your experiences as well as the deceased individual's experiences from your perspective. You must be age 18 or older to be in this study. This study is not approved for the enrollment of people under the age of 18."

A Pediatric Case Definition for
Myalgic Encephalomyelitis
and Chronic Fatigue Syndrome

Issues Involving the Name Change Recommendations
Leonard A. Jason, Nicole Porter, Jennifer Okasinski, & Mary Benton -
DePaul University

Read more about Dr. Jason's Research Team (sidebar background photo) and their work.

"...among this sample of participants with [M.E.]
CFS, causes of death appear to cluster in three general domains: heart failure, suicide, and cancer. For each of these areas, there is supportive evidence that might help explain why heart failure, cancer, and suicide might be associated with deaths among people with CFS in this sample."

the possible cause of one patient's illness to 'self-imposed stress of
her ambitious lifestyle' suggests a psychogenic explanation. Given that
most Americans have an 'ambitious' lifestyle, tend to be highly over-active and over-committed, and as a consequence sleep less than a few decades ago, one might ask why everyone in this country has not developed this disorder?"

"Stress is also a contributor to such 'biological' disorders as cancer, hypertension, heart attacks, etc. but we don't tell people with heart disease that they are overachievers and, therefore, personally blame them for their illness."

"Surely, we would want to help the person deal with the negative emotions caused by the disease, but to suggest that the negative emotions caused the illness is a form of victim blaming."

"Full recovery from CFS appears to be rare in adults, with an average of only 5% to 10% of subjects sustaining total remission."

"To suggest that efforts to help people cope with a chronic illness is the primary and
only way to cure them does a disservice to all individuals with this condition."

"There is a clear need to fund basic science research focusing on issues involving criterion variance, and problems with the current syndromes might be due to inadequate formal inclusion and exclusion criteria used to classify patients’ data into diagnostic categories. Criterion variance is likely to occur when explicit criteria do not exist for diagnostic categories.  For example the US case definition of CFS treats two central symptoms, post-exertional malaise and cognitive impairment, as optional rather than required criteria."

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