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Study: ‘Brain Fog’ persists among COVID-19 long-haulers

Comparing long-haul COVID-19 with chronic fatigue syndrome reveals diverging symptom patterns, find researchers at DePaul University. (iStock.com/nensuria)


CHICAGO — As people with long-haul COVID-19 continue to recover from their illness, neurocognitive symptoms may persist or even worsen over time, as reported in new findings from researchers at DePaul University. Psychologist Leonard A. Jason led the study comparing those with long-haul COVID-19 with patients who have myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Comparing long-haul COVID-19 with another chronic illness could help researchers uncover root causes of long-term illness and inform their approach to care, Jason said. Many other symptoms of long-haul COVID-19 do appear to improve over time, which diverges from the experience of most with ME/CFS. Findings were published in the journal “Fatigue: Biomedicine, Health & Behavior” and are available at http://bit.ly/LJ_C19​.

“The symptoms hanging on most for COVID-19 long-haulers are sometimes referred to as ‘brain fog.’ People have trouble problem solving, or they get in the car and forget where they’re supposed to be going,” said Jason, director of the Center for Community Research at DePaul. Researchers defined long-haul COVID-19 as having serious, prolonged symptoms three months after contracting the SARS CoV-2 virus.

Researchers surveyed 278 long-haul COVID-19 patients about their symptoms at two points, six months apart. They also surveyed 502 ME/CFS patients about their symptoms, which have significant overlap with COVID-19. Jason and his team used the DePaul Symptom Questionnaire, a self-report measuring tool developed for use with ME/CFS patients. Researchers found:


  • At the six-month mark, COVID-19 long-haulers report worse neurocognitive symptoms than at the outset of their illness, including trouble forming words, difficulty focusing and absent-mindedness. Still, these symptoms were ranked less severe than those with ME/CFS. 
  • Most other symptoms, including sleep problems, immune-related issues, pain and gastrointestinal issues, seem to improve over time for COVID-19 long-haulers. 
  • The most severe symptom for COVID-19 long-haulers and ME/CFS patients alike was post-exertional malaise, which includes feeling physically and mentally drained or heavy.


These findings may provide other researchers with insights into nervous system pathophysiology, such as that found in patients with ME/CFS. While ME/CFS is known to have many triggers, including the Epstein-Barr virus, not every patient knows what led to their illness, noted Jason. However, COVID-19 long-haulers have a single virus to point to as the initial cause of their symptoms. Both groups face similar challenges as their family members and health care workers may not understand the changing symptom patterns.

“We don’t know how many long-haulers will stay on this type of trajectory,” Jason said. He and other researchers estimate about 10% of people who have COVID-19 become long-haulers. In reviewing the literature, the researchers found that past epidemics, including the 1918 pandemic, have also led to many patients having long-term fatigue.

“These types of serious neurocognitive complications are incredible given that millions of people have been infected,” Jason said.

DePaul Center for Community Research co-authors on the study include Mohammed Islam, Karl Conroy, Joseph Cotler, Chelsea Torres, Mady Johnson and Brianna Mabie. Funding for this research was provided by the National Institute of Neurological Disorders and Stroke (grant number 5R01NS111105).

Leonard Jason

Media Contact:
Kristin Claes Mathews

NIH-Funded Study Examines Mono, CFS in College Students

Researchers in Chicago conduct longitudinal study of 4,500 undergraduates

CHICAGO — Many college students fully recover from infectious mononucleosis (which is almost always caused by Epstein-Barr virus) within 1-6 weeks, but some go on to develop chronic fatigue syndrome, also called myalgic encephalomyelitis (ME/CFS). A longitudinal study from DePaul University and Northwestern University followed 4,501 college students to examine risk factors that may trigger longer illness. The research appears in the journal Clinical Infectious Diseases and was funded by the National Institute of Allergy and Infectious Diseases.

Previous retrospective studies found that risk factors for developing ME/CFS after catching mono included preexisting physical symptoms and the number of days spent in bed, according to co-principal investigators Leonard A. Jason, professor of psychology at DePaul University; and Dr. Ben Z. Katz, a professor of pediatrics at Northwestern University’s Feinberg School of Medicine and a pediatric infectious disease specialist at Ann & Robert H. Lurie Children’s Hospital of Chicago.

Professor Leonard A. Jason
Leonard A. Jason is a DePaul University psychology professor who has studied chronic fatigue syndrome for the past 30 years. He also is director of the Center for Community Research in DePaul’s College of Science and Health. (DePaul University/Jamie Moncrief)

“We are the only study to collect comprehensive biological and behavioral data prior to illness onset, which for the first time allowed us to identify some of the predisposing circumstances or conditions that make certain individuals more likely to get ill due to mono and stay ill,” said Jason, director of the Center for Community Research at DePaul.

Of the 4,501 college students in the study, 238 or 5.3% developed mononucleosis; and 55 of those (23%) met criteria for ME/CFS six months later, 20 of whom (8%) met criteria for severe ME/CFS. Researchers found that those who developed ME/CFS had more physical symptoms and immune irregularities at baseline, but they did not start out with statistically significantly more psychological symptoms such as stress, depression, anxiety or abnormal coping.

“Some people who are attacked by a virus stay sick. What we’ve found is that their emotional functioning and psychological states are not statistically different from those who get attacked by the same virus and recover. This becomes important validating information for those people who have this illness,” said Jason.

Dr. Ben Z. Katz
Dr. Ben Z. Katz is a pediatric infectious disease specialist at the Ann & Robert H. Lurie Children’s Hospital of Chicago. He also is a professor of pediatrics at Northwestern University Feinberg School of Medicine. (Lurie Children’s Hospital/Jan Terry)

Participants in the study each completed seven different surveys to assess potential symptoms of ME/CFS. They also received a comprehensive psychiatric exam, and provided samples of serum, plasma and white blood cells. In future publications, researchers aim to analyze cytokine networks in participants’ blood and other risk factors. Deficiencies in certain cytokines “might suggest predisposing irregularities in immune response,” wrote the researchers.

Vicky Whittemore, the program director at the National Institute of Neurological Disorders and Stroke (NINDS), stated that NINDS is supporting follow-up research to continue to study this cohort, and to examine possible predictors of COVID-19 as well. “Since we have baseline data on nearly all of the 4,500 students, we can use our same database to tease out risk factors for COVID infection as well as prolonged recovery from that illness” said Katz.

Other co-authors on the study are Joseph Colter, Mohammed F. Islam and Madison Sunnquist of DePaul’s Center for Community Research. The study, “Risks for Developing ME/CFS in College Students Following Infectious Mononucleosis: A Prospective Cohort Study” was supported by the National Institute of Allergy and Infectious Diseases, grant number AI 105781. The full study is available at http://bit.ly/MECFS_2021.


Psychologists Earn $6.6M Grant for Youth Violence Prevention Project

Psychology professors W. LaVome Robinson and Leonard A. Jason have earned a $6.6 million grant from the National Institute of Mental Health to reduce African American youth violence. The award is the largest research grant DePaul University has ever received. 

With collaborators including Chicago Public Schools and Rush University Medical Center, the Success Over Stress Violence Prevention Project strengthens ninth graders’ coping skills to deal with stress in order to promote resilience and prevent interpersonal violence and suicide. 
“In communities hard-hit by poverty and drugs, children witness violence and it leads to more violence. Children in these environments do what they do because they’re trying to survive,” says Robinson, principal investigator for the study. “We are giving children ways to minimize the likelihood they are going to be exposed to, participate in or experience violence.” 
Robinson has led Success Over Stress through two efficacy trials, with trained clinicians facilitating the 15-session course in CPS. This yielded strong results: 80 percent of students reported the course helped them meet their stress-reduction goals. NIMH is now funding this 5-year “real world” effectiveness trial, which will train social workers in CPS to deliver the course. This next step is critical for discovering methods to sustain and even expand this intervention model within school systems. 
“We’ve been talking about this for years and we’ve finally made it,” Robinson says. “It’s a very big deal to go from efficacy to effectiveness—very few researchers are able to do that. This wasn’t quick and dirty; it was slow and deliberate.”
Robinson and Jason, co-investigator on the study, have been collaborating at DePaul for nearly 40 years. 
“We often think about research, teaching and practice as being separate. But this is all three, and that is the best of DePaul,” says Jason, director of DePaul’s Center for Community Research. 
Evidence-based approach to stopping violence 
Robinson notes there are many programs to address youth violence, but few have been as rigorously evaluated as Success Over Stress. 
“People are asking ‘What do we do about gun violence? What do we do about school violence?’ There are a lot of people doing good work, but not a lot of empirically validated solutions. We aim to change that,” Jason agrees. 
In previous trials, researchers enlisted CPS students to help tailor the scenarios, names of characters and stressors to ensure the program would resonate with their peers. Students shared experiences common among African American youth, Robinson says, from being followed around inside a store and suspected of stealing, or being profiled by police on the street. 
“These children are trying to develop under enormous stress. Any individual with the right amount of stress will seek to cope with that stress,” Robinson says. “We help the children recognize stressors in advance, to anticipate the stressor and prepare for the stressor, so they don’t get overwhelmed and do impulsive kinds of things.”
According to Jason, it’s rare for researchers to go into the field and gather information from youth who will receive an intervention. He believes this program has potential for greater impact once it can get into the hands of more social workers in Chicago and beyond. 
“A lot of researchers come in and say, ‘We have the solution and know what’s best for you.’ Instead, we’re trying to augment the natural resilience the children already have,” he says. 
Education and collaboration, a ‘Vincentian approach’ 
With this and other grants, the researchers enlist undergraduate and graduate psychology students at DePaul to help deliver and evaluate the program. Working in the Center for Community Research has helped hundreds of psychology alumni gain entrance to graduate programs and launch their careers, Jason says. 
“That’s powerful. We are giving our students the credentials, training and experiences that make them marketable,” he says.
Alumnus Christopher Whipple contributed to the research during his graduate studies at DePaul and says he was impressed with how youth in the program would encourage each other. 
“Assisting with the implementation and evaluation of the Success Over Stress program helped me to recognize the capacity of youth to strengthen their peers and make lasting change in their communities,” says Whipple, who now teaches psychology at Penn State Harrisburg. 
Other collaborators on the project include Rush University Medical Center and Heartland Health Centers, which administer the school-based health centers in CPS. Co-investigators are Kate Keenan, professor of psychiatry and behavioral neuroscience at the University of Chicago; Sally Lemke, director of community health clinics at Rush University Medical Center; and Donald Hedeker, professor of biostatistics at the University of Chicago. 
“Collaboration can be the best way to solve problems, and that is very Vincentian,” Jason says. 
Longtime collaboration a ‘shining example’
Much has changed at DePaul since Robinson and Jason began working together in 1980. Along with their colleagues, they have helped the community psychology program grow over the years to more than 700 undergraduate and 100 graduate students. The Center for Community Research opened in 2001, and faculty and students in the center have drawn some $39 million in research grants to the university. 
“This grant is a shining example of the cutting-edge, relevant research that occurs in our college,” says Dorothy Kozlowski, interim dean of the College of Science and Health. “Professors Robinson and Jason are leading the way, making significant contributions in their field and making a difference in the lives of children and families in underserved areas of Chicago.”
DePaul University has always valued a teacher-scholar model, which integrates innovative research into the education of the next generation, says Daniela Stan Raicu, associate provost for research. 
“This award is significant because it can be a catalyst for new opportunities for students to get engaged in research, for faculty to spearhead new interdisciplinary collaborations throughout the university, as well as for the Center for Community Research to draw further support for its important work,” Raicu says.​



The Myth of “It’s All in Your Head”

DePaul scientists work to unravel the mystery of chronic fatigue syndrome

By Abigail Pickus

In 1980, a high school English teacher from Wisconsin named Pat Fero went on a trip to England. Healthy and in her 30s, she noticed something was very wrong toward the end of the trip.

“We were in this beautiful countryside, and we went to climb a hill to get a better view of a lake and I just couldn’t do it. I thought, I am really out of shape. I couldn’t get up that hill. My legs hurt, and I was dizzy and short of breath,” recalls Fero.

When she returned home the fever hit.

“I had a 104° fever for a week and a headache from hell. I had extreme pain in my neck and shoulders that lasted another week,” she says.

Over the next few years she got progressively sicker until she couldn’t climb the stairs at school without resting on the landing. Then she was unable to write on the chalkboard. “I would misspell things. I couldn’t form the letters correctly. I would miss words. Day-to-day communication became tough. That’s why I left the classroom. You can’t be in front of 20-some kids and seriously not know what you’re talking about,” she says.

In 1988, Fero went on medical leave—and never returned. That was the year she finally received a diagnosis for her suffering: chronic fatigue syndrome.

Mystery Disease

Tragically, Fero is not alone. Using research data developed at DePaul, the Centers for Disease Control and Prevention (CDC) estimates that there are currently more than1 million people in the U.S. and more than 17 million worldwide with chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME)—and these are just the ones who have been diagnosed. (See What’s in a Name?)

Often triggered by a virus, this debilitating disease continues to plague people for years with symptoms that run the gamut from nerve pain and cognitive impairments to a fatigue better characterized as bone-crushing exhaustion.

“Don’t use the word fatigue. It’s an exhaustion so severe that you can’t stand up because you feel like you’re going to faint,” says Fero.

Often lumped together with other so-called “mystery illnesses” such as Lyme disease and fibromyalgia, CFS/ME is historically misdiagnosed or underdiagnosed simply because one of its defining symptoms—fatigue—is both commonplace and seemingly benign. Adding insult to injury, CFS/ME is notoriously stigmatized because of its name “chronic fatigue,” suggesting that the patient is merely tired.

But the medical community is baffled, from what causes it to what it really is: A brain disease? A virus? And with federal funding for research into CFS/ME improving but still lower than for other major diseases, the quality of life for millions of Americans is left hanging in the balance.

Enter Leonard Jason, a professor of psychology at DePaul, who with his team has been making serious inroads into cracking the code on this mystery illness. “DePaul has been trying to validate the experience of patients with CFS/ME, to find ways to lessen the burden of this illness by reporting on accurate prevalence numbers among adults and children, to find effective treatments and to understand its etiology,” says Jason.

It’s a tall order, but with more than 800 professional publications and 25 books to his name (many on CFS/ME), plus more than $36 million in research grants, Jason and the DePaul Center for Community Research have emerged as leading figures in an area of medicine otherwise shrouded in darkness.

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How Chronic Illness Can Influence Suicide Risk

contributed by Dr. Lily Chu

Contrary to popular belief, up to 50% of people who die by suicide may not be affected by a mental health condition. A substantial majority though had visited a healthcare provider in the previous year. These findings suggest that physical health, and not only mental health, may impact suicide risk.

One physical health condition that may increase suicide risk is myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS). In fact, suicide may be the number one cause of death for people afflicted by ME/CFS. Most of the public and many healthcare professionals have never heard of this disease. Others might have been exposed to wrong or obsolete information. Crisis center staff and volunteers may encounter callers affected by ME/CFS. We share basic facts about ME/CFS and concrete steps crisis centers can take to help callers. By the end of this post, you will know more about this disease than most physicians!

Have you ever heard of or read about ME/CFS? Share your thoughts, experiences, and questions by commenting below.

What is myalgic encephalomyelitis/ chronic fatigue syndrome (ME/CFS)?

ME/CFS is a chronic, complex, medical condition which affects at least a million Americans. That makes it more common than better-known conditions like multiple sclerosis or Parkinson’s disease. In the past, ME/CFS was believed to affect primarily upper-middle class, Caucasian, middle-aged women. Later studies showed that people of both sexes and all ages, races, and socioeconomic background can be affected.

ME/CFS often strikes people in their teenage or early adult years following common infections like Epstein-Barr virus mononucleosis (popularly called “mono”). For reasons we don’t understand yet, about 10% of people who fall ill do not recover and develop ME/CFS in the subsequent days to months. Current evidence does not suggest ME/CFS is contagious. Rather a persistent dysregulation of the immune system may have resulted in uncontrolled/ re-awakened infections or an autoimmune process in the sick individual.

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Becoming a Great Mentor

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The Hidden ME-Too

The hidden ME too: 100,000 people in Illinois could suffer from debilitating disease

Chicago researchers are searching for a cure for ME,
which is more widespread and serious than previously thought.
by Megan Doherty

What if, on a daily basis, you had to choose between taking a shower or doing laundry? Making dinner or taking out the trash? Reading a book or catching up on e-mail?

You need to pick. You can’t do both today.

If you do, you’ll suffer for it.

These are the kinds of calculated trade-offs that people suffering from myalgic encephalomyelitis (ME) are forced to make. Our lives exist on the razor’s edge between functioning and crashing.
I say “our” because this is now my life, too. With a relatively mild case, I can walk and talk—except for those times I can’t.

ME is a debilitating neuroimmune disease recognized by the World Health Organization since 1969. Yet it was given what many advocates say is a misleading set of diagnostic criteria and a trivializing name, chronic fatigue syndrome, by researchers at the U.S. Centers for Disease Control 30 years ago. This moniker doesn’t do justice to what patients suffer, which includes an array of symptoms that can go far beyond unrelenting fatigue. From neurological to cardiovascular, ME affects nearly every system in the body—especially if you do too much. That crash after exertion of any form makes everything worse.

And by “worse,” I mean near-paralytic muscle weakness and the feeling you’ve been poisoned.

Not surprisingly, a Danish study of the quality of life experienced by those with a range of diseases found that people with ME have the lowest scores of those suffering from diseases, including multiple sclerosis, chronic renal failure, stroke, lung cancer, diabetes, and heart failure. A quarter of ME patients are homebound or completely bedridden, and as many as nine in ten lose their jobs because of the illness, according to the Solve ME/CFS Initiative, an advocacy group. The economic cost in lost productivity and health care expenses is estimated to be in the billions, according to a report by the National Academy of Medicine. That report also estimates that there are up to 2.5 million people with ME in the U.S., with up to 91 percent of cases undiagnosed. That would amount to nearly 100,000 people in Illinois, and would make the disease more common than Parkinson’s, multiple sclerosis, or HIV/AIDS.

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Defining Community Psychology


2019 (April 18). Leonard Jason, Academic Minute. Most people think of psychologists in very traditional ways.   http://bit.ly/LJasoAM

Psychologists are more than therapists.

Leonard Jason, professor of clinical psychology at DePaul University, examines the field of community psychology.

Leonard Jason is a professor of clinical and community psychology in DePaul University’s College of Science and Health. He’s also the director of DePaul’s Center for Community Research. A DePaul faculty member since 1975, Jason’s research interests include chronic fatigue syndrome and myalgic encephalomyelitis, recovery homes, school violence and methods for prevention, smoking and methods for prevention, media interventions, children and media, and community building. He’s an editorial board member for the Journal of Community Psychology, the Journal of Prevention and Intervention in the Community, the Journal of Health Psychology, and Fatigue: Biomedicine, Health & Behavior. He’s the author of the 2013 book, Principles of Social Change. Jason holds a Bachelor of Arts in psychology from Brandeis University and a doctorate in clinical and community psychology from the University of Rochester.


Defining Community Psychology


Most people think of psychologists in very traditional ways. For example, if you were to close your eyes and imagine one, there is a good chance you would think of a therapist.

My field is called community psychology, and it is a wonderful blend of psychology and sociology. It creates new roles and opportunities for psychologists by extending the reach of services to those who have previously been under-represented. It also focuses on prevention rather than just treatment of psychological problems and on actively involving community members in the change process. In a sense, we are like community organizers but specifically trained to be able to evaluate whether or not our social justice interventions are effective.

The field of community psychology focuses on preventing — rather than just treating — psychological problems. In fact, no condition or disease has ever been eliminated by focusing just on those with the problem. An impressive example of prevention occurred with community efforts to change the landscape of tobacco use over the past 50 years. Today, attitudes have changed toward tobacco use and there are substantially fewer smokers. Community organizations aided by community psychologists made important contributions to these efforts.

The community psychology approach shifts the power dynamic to a less hierarchical, equal relationship, as all parties participate in the decision-making process. Community members are seen as resources, who provide unique points of view about the community and the institutional barriers that might need to be overcome in social justice interventions.

Community psychology’s focus on social justice is due to the recognition that many of our social problems are created when resources are disproportionately allocated throughout our society, which causes social and economic inequalities such as poverty, homelessness, unemployment and crime.

It’s important that we as a society continue to look for transformative ways of solving social problems, and community psychologists are here to help.


A Q&A with Leonard Jason on case definition


By David Tuller, DrPH

Leonard Jason is a professor of psychology at DePaul University in Chicago. He has served as vice president of the International American Association of CFS/ME and as chairperson of the Research Subcommittee of the U.S. Chronic Fatigue Syndrome Advisory Committee. Professor Jason began investigating chronic fatigue syndrome almost 30 years ago. Much of his work has focused on the epidemiology and prevalence of the illness and on the impact of using various case definitions. He has long been concerned that the lack of a uniform set of criteria for identifying study participants has hindered progress in the science.

Dr. Jason recently shared his thoughts about these issues. (This Q-and-A has been edited for clarity and length.)

How common is fatigue?

If you were to ask people right now if they are “fatigued,” which means feeling weak, tired, or lacking energy, about 25% of the population would say yes, so this symptom is very common. In contrast, “chronic fatigue” means that a person has had fatigue for 6 or more months. Only about 4-5% of the population has chronic fatigue.

There are multiple reasons for people to be fatigued–for example depression, anxiety, over-exertion, people working three jobs, medications, sleep deprivation, weight problems, poor diet, inactivity, and deconditioning. These are just a few of the many causes of fatigue and chronic fatigue.

Physicians see lots of people coming into their practices, where the patients are seeking help for their fatigue, and in fact it is one of the most common reasons for seeing a doctor. But it’s very hard for many physicians to differentiate complaints of general or chronic fatigue versus the illness known as ME [myalgic encephalomyelitis]. Yet it is of critical importance to make a differential diagnosis between those with purely chronic fatigue versus those who have ME. In fact, it is this failure to differentiate these two conditions that has caused so many problems, and the culprit is a flawed and imprecise case definitions as well as failures to gain an international consensus for one research case definition.

So what is a case definition, and why are there different research and clinical definitions?

A case definition is a set of rules that helps a researcher or a clinician make a decision about whether someone has a particular illness or does not have the illness. It’s that simple. A good case definition is critical for the assessment process, to identify those people who actually have an illness or disease. It is the cornerstone of medicine.

A research case definition tries to identify a homogeneous group of people who have the illness and can be recruited for research purposes. In contrast, a clinical case definition is used to identify or diagnose a broader group of patients for treatment purposes, and many of these wouldn’t qualify for research studies. For example, if someone is very obese, a research case definition might exclude that person because the weight issue could be causing the person’s problems. In other words, for research purposes, we want to select only patients who do not have other psychological or medical conditions that could be causing the illness we are studying.

For science to progress, the research case definition is critical, as it can standardize the selection of patient samples so that research groups around the world are all studying the patients with the same disease. So gaining consensus among international scientists for a research case definition is a most critical task, and one that unfortunately has still not been accomplished for our field.

One of the parameters that’s important for a research case definition for this illness, in your view, is that psychiatric co-morbidities should be excluded. Can you explain the reason for that?

Yes, and let me give an example that illustrates this issue. A patient with a major depressive disorder with melancholic features would probably have fatigue, aches and pains, as well as sleep and cognitive problems. Yet these are also symptoms of ME, so some clinicians and researchers could easily confuse these two conditions. But they are very different illnesses, as people with a major depressive disorder feel self-reproach, whereas those with ME do not. If you ask people with a major depressive disorder what they would do tomorrow if they were well, they would not be sure. In contrast, if you asked people with ME what they would do if they were well, they’d give you a long list of all the things they have wanted to do but been unable due to their illness.

If you are studying ME, you need to exclude people who have a primary psychiatric disorder from your study. If researchers misclassify people with a major depressive disorder as having ME, this will have serious negative consequences for identifying biomarkers, estimating prevalence rates, and determining outcomes of treatment trials. The issue of selecting patients who really have ME is the most important issue facing our field. In a sense, the lack of a consensus on a ME research case definition is like building a pyramid of playing cards with a very shaky bottom, and then everything built on top of this foundation is vulnerable to collapsing.

Let’s start with what is the broadest case definition that has been used, the so-called Oxford criteria for CFS. Can you describe that and explain why it presents a problem?

If you have six or more months of fatigue, then you meet this case definition, so it’s a very broad category. Clearly, as I mentioned earlier, a lot of people who meet this criteria have medical or lifestyle reasons causing their fatigue. One of my students, Madison Sunnquist, just published her master’s thesis that indicated how the CBT theoretical model only works if you identify people with a very wide case definition, but when you have a better and more restricted case definition that requires core symptoms of ME, then the CBT model no longer works. In contrast to the CBT approach, my research group for the past 20 years has been doing research on what we call the energy envelope. But this pacing approach is not a cure, just a strategy to help better cope with ME. Our approach involves helping patients to better monitor their energy levels, learn how to stay within their energy envelope, and sustain lifestyle changes that involve reprioritizing activities.

So how did the CDC come up with the Holmes and then the Fukuda case definitions?

The Holmes case definition came out in 1988. The CDC investigators had gone to Incline Village and ultimately named this illness CFS. Their first case definition included too many symptoms. In fact, to meet their case definition, a patient would have needed to have eight or more symptoms out of a list of 11. But here is the problem that soon emerged–if you develop a case definition that requires so many unexplained somatic symptoms, you have a very high probability of unwittingly selecting people who have a somatoform disorder. And you don’t want to select people who have a purely psychiatric condition.

So in 1994, the Fukuda case definition was developed to replace the Holmes definition. For the 1994 case definition, the authors selected eight of the symptoms that had been listed in the Holmes criteria, and a patient needed to have any four of those eight symptoms to meet the new Fukuda case definition.

But here is the problem with the Fukuda CFS case definition–patients are not required to have post-exertional malaise, cognitive problems and unrefreshing sleep, and as we know, these are core symptoms of ME. So, a person could have four of the eight Fukuda symptoms and be diagnosed with CFS, and not have any of the three critical symptoms. In that case, you would be including in your sample a person who does not have the core elements of the illness.

From 1994 and on, I have been doing research that shows some of the diagnostic problems with the Fukuda case definition. And remember, the Fukuda case definition is the research case definition that has been used throughout the world for the past 25 years. But this Fukuda case definition identifies a heterogenous group of patients, because core symptoms are not required of all patients. So, as a consequence, samples of patients with CFS based on Fukuda case definition vary widely in different research groups and labs.

What is the impact of the case definitions on prevalence rates?

In the late 1980s and early 1990s, the CDC conducted a prevalence study where they started by asking physicians in four cities to identify patients they thought had CFS. At that time, a lot of physicians didn’t believe CFS existed, so putting physicians as gatekeepers in the selection of patients for this study resulted in a prevalence rate that was very low. Also, many people in the US do not have the financial resources to have a physician, so relying on primary care doctors to identify patients was another reason for low prevalence rates. The study suggested that CFS was a rare disease that affected fewer than 20,000 people in the US.

At that point, a group of researchers in Chicago began working on a study that involved finding patients from a random community sample, rather than a sample referred from physicians. In 1995, with NIH funding, our Chicago research team conducted a community-based prevalence study, which found that about a million people in the US had CFS. We also found that CFS affected all ethnic and socioeconomic groups, and thus we helped shatter the myth that CFS was a “Yuppie Flu” disease.

What did William Reeves [then-head of the CDC division in charge of the illness] do with the so-called “empiric” criteria? And why did this increase the CDC’s estimate of disease prevalence by a factor of 10?

In the early 2000s, Bill Reeves felt there was a need to operationalize the Fukuda case definition. For example, he tried to standardize the way we measure a patient’s disability or a substantial reduction in functioning. He used one instrument that has been referred to as the SF-36. According to Reeves, if a patient met criteria for one of several sub-scales within the SF-36, the patient would meet the disability criteria for having CFS.

But one of these domains was “role emotional” functioning. It turns out that every person with a major depressive disorder meets the criteria for “role emotional” functioning. So you can’t just specify instruments such as the SF-36; you have to specify which sub-scales of the instruments you are going to use, and what are the cut-off points. And if any of these choices are wrong, you will identify people who have another illness. My team gathered data on this point, and we conducted a study that assessed people with major depressive disorder, and found that over one-third of them could be inappropriately classified as having CFS under the so-called Reeves empiric criteria.

So, I think in the attempt to operationalize the Fukuda criteria, Reeves made mistakes, and I believe that is one of the reasons the estimated CDC prevalence estimates increased ten-fold, from .24% in a 2003 sample to 2.54% in 2007. They operationalized the Fukuda criteria in a way that classified many people as having CFS when they really had other illnesses.

At that time, many thought this increase in prevalence figures that Reeves proposed was constructive as it suggested that far more people had the illness, and thus these findings could be used to argue for more attention and funding due to this illness being so widespread. But if you use a very broad criteria, and bring into the illness case definition people who don’t have the disease, then the entire research effort is seriously compromised. Fortunately, over the past decade, few researchers have used the Reeves way of operationalizing CFS.

What about the CCC and ICC criteria?

The CCC case definition for ME/CFS in 2003 was better because it specified key symptoms such as PEM. It was developed as a clinical case definition, and now it’s being used by several teams as a research case definition. With the 2011 ME-ICC, I have noticed problems, and in part this is due to them once again requiring too many symptoms that could, as with the Holmes criteria of 1988, bring into the ME category some individuals who have a primary psychiatric disorder. In addition, the ME-ICC criteria is complicated to use, and many clinicians and scientists will have a difficult time reliably using it with patients.

What is the problem you see with the IOM case definition, apart from the name?

Well, it is true that Systemic Exertion Intolerance Disease (SEID) is a name most patients dislike. However, the IOM report was correct in requiring several core symptoms, such as PEM. But I believe these authors made a mistake in indicating that a patient could have either cognitive impairment or orthostatic intolerance—one or the other. Cognitive impairment should have been required for all patients to have. But a more serious problem is that they inadvertently expanded the case definition by having just about no exclusionary illnesses, such as primary psychiatric disorders. My team recently conducted a study where about half the people with a variety of medical and psychiatric illnesses met the IOM criteria.

Now the IOM criteria was developed as a clinical case definition, but there was no federal effort to develop a research criteria that selects a more homogenous group of patients. The failure to develop an international consensus on a research case definition means that many researchers will continue to use the problematic Fukuda case definition, or they might use the IOM clinical criteria to select patients for research purposes, and this process has already begun.

To summarize, for research purposes, if a person has the core symptoms of the IOM definition, it would be important to exclude those with a primary medical or psychiatric condition, but this is not what the IOM authors recommended. So, the clinical IOM case definition once again over-identifies people as having the illness. That means what occurred with the Reeves criteria of a decade ago has once again occurred with the IOM, as these criteria broaden the types of patients identified as having the illness.

What is at stake in this debate?

The stakes are high, for if you have an inappropriately wide case definition for research purposes, you will bring into your studies many fatigued people with a variety of conditions. In other words, if you identify the wrong patients, then your study will make conclusions about people who do not have ME, and you will have significant barriers to engaging in critical scientific activities such as estimating accurate prevalence rates or identifying biological markers. Also, if you bring in lots of people who don’t have this illness but lifestyle issues and/or a solely depressive disorder, a good percentage of them will respond favorably to psychogenically oriented treatments. As I have been writing about for many years, this will ultimately lead to some researchers making conclusions about CBT and GET that are not true for patients with ME.

My case is simple. You need to have one research case definition that is used by scientists throughout the world. The clinical case definition can be broader, but the research case definition has to be tightly focused on those with the illness so that results can be replicated in different laboratories. This scientific achievement has been accomplished with every illness or disease except for ME.

We can do better. After working in this area for almost three decades, I am confident that we have the tools and methods to use psychometrically sound procedures to develop a consensus on one research case definition. I am optimistic that one day this will occur, and for me, there is literally nothing as important for our scientific field.

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Leonard A. Jason is a professor of clinical and community psychology at DePaul University, director of the Center for Community Research, and the author of Principles of Social Change and co-editor of the Handbook of Methodological Approaches to Community-Based Research: Qualitative, Quantitative, and Mixed Methods.

When sickness interrupts science

2018 (Jan. 10). Nature. Emily Sohn. When sickness interrupts science. How to balance a long-term illness and a research career.

Click here to read this article on Nature.com


Navigating a research career along with a chronic illness, say many researchers, requires zeroing in on what is most essential. Leonard Jason, a psychologist who was diagnosed in 1989 with myalgic encephalopathy/chronic fatigue syn­drome (ME/CFS), realized that he needed to be strategic about his work and careful not to over­tax himself. His approach has led to recognition, including awards for excellence in research and, at one point, a position on a US federal panel advising about research on ME/CFS. He recommends that scientists pursue the work that matters most to them. “The reality is that you can’t do it all,” says Jason, of DePaul University in Chicago, Illinois. “Prioritization is absolutely critical when one is in a dimin­ished state. If it’s trivial and you don’t care about it, let it go.”

Leonard A. Jason is a professor of clinical and community psychology at DePaul University, director of the Center for Community Research, and the author of Principles of Social Change and co-editor of the Handbook of Methodological Approaches to Community-Based Research: Qualitative, Quantitative, and Mixed Methods.