PEM Is Bad and So Is Fukuda, New Study Finds

By David Tuller, DrPH

A new study in the Journal of Psychosomatic Research, posted December 16th, has reported that patients with chronic fatigue syndrome who experience major post-exertional malaise have a greater burden of psychological distress than those whose PEM is minimal or non-existent. Of course, this is not surprising. The sicker people are, with this or any illness, the more likely it is they will  experience depression or related emotional turmoil for any number of reasons—the impacts of poor health, discrimination at work, lack of understanding from family and friends, etc.

Yet the paper couches these findings in language that suggests patients are possibly or likely responsible for keeping themselves sick. And the authors appear to overlook the main implications of their own findings.

The corresponding and senior authors are from the psychology department of the University of Miami. Co-authors include Nancy Klimas and Mary Anne Fletcher from Nova Southeastern University, in Fort Lauderdale. (In what appears to be an error, Dr Klimas and Dr Fletcher are listed in the author credits as being affiliated with NSU’s psychology department, when the university’s website indicates that both are affiliated with the Dr. Kiran C. Patel College of Osteopathic Medicine. The journal has reviewed and accepted the article, but it is still “in press” and the available text is the “pre-proof,” so perhaps it is still undergoing corrections.)

For the study, the authors examined data from 261 patients diagnosed with the so-called Fukuda-CDC criteria. This 1994 case definition predominated in clinical care and research for decades but is increasingly being supplanted by newer (and also often contested) criteria. Fukuda requires prolonged fatigue plus four of eight other symptoms. PEM is one of the eight; that means people can be defined with the illness but not have PEM at all. Newer criteria all require the presence of some form of PEM, however defined.

In the symptom questionnaire completed by patients in the JPR study, PEM was identified as “unusual fatigue following exertion that lasts for at least 24 hours.” Patients were split into two groups based on their PEM experience. The 139 patients who described their PEM as “severe” or “very severe” were compared to the 122 who described it as “moderate,” “mild,” or “very mild,” or who did not indicate that they had it at all.

Not surprisingly, patients who reported worse PEM also scored more poorly on various dimensions measured, both physical and psychological. As the authors write: “This study replicates the association between PEM and symptom burden and additionally associates PEM with psychological distress.” The measures of psychological distress included indicators of “social disruption, depressive symptoms, and mood disturbance.”

Of course, like anyone with or without a debilitating chronic illness, patients might benefit from some form of psychotherapy or counseling to address mood disorders and related issues, whether arising as a direct result of being sick or from other factors. And yet the JPR paper suggests—without apparent evidence—that these psychological matters themselves might be impeding the ability of CFS patients to recover.

Here’s what the authors write in their introduction: “As a general exacerbation of CFS symptoms, PEM is likely to have substantial effects on patients’ quality of life and be uniquely distressing in psychological terms. It is also possible that PEM inhibits patients from engaging in physical or cognitive exertion, thereby precluding them from the benefits of such pursuits and sustaining the expression of CFS. Seen in this light, PEM could play a role in the maintenance of CFS phenomenology by way of its psychological effects.”


And this line of argumentation continues in the discussion section: “Because this psychological distress is a potential maintaining factor of CFS (i.e., by inhibiting patients from engaging in tasks requiring physical or cognitive exertion and thereby compromising quality of life), PEM may also identify those patients who are in the greatest need of and would potentially benefit the most from psychological intervention.”

In a neutral context and with regular diseases, this framing and phrasing might not trigger alarm bells. However, when it comes to CFS or ME or the illness (or cluster of illnesses) variously meant by these terms and others, there is obviously a long and sorry back-history of patient-blaming that parallels this line of argumentation. What the JPR authors suggest here clearly resembles the unsupported ruminations and ramblings of the CBT/GET ideological brigades. The apparent assumption is that patients are exacerbating their condition through an avoidance of activity, rather than that they avoid activity because that’s how they avoid exacerbating their condition.

The paper itself offers no coherent explanation for why this activity avoidance and the consequent “compromising of quality of life” have been construed as being a “maintaining factor of CFS.” What is the mechanism by which this purported maintenance of CFS symptomology occurs? The authors present the proposition as if this claimed causal pathway from sedentary behavior to perpetuation of illness is, you know, uncontested–something we all agree on. That assumption should have been challenged by reviewers, editors or anyone who read the draft.

Yet when a published paper gets its own declared “highlights” wrong, readers can be forgiven for wondering whether other things might be amiss. One of the study’s four stated highlights is this: “Results suggest the Fukuda case definition does not define a heterogeneous group.”

In fact, that’s the exact opposite of what the study found; according to the authors, the results demonstrated “the heterogeneity of diagnoses resulting from the Fukuda criteria.” In the highlight, the word “heterogeneous” should clearly be replaced with “homogeneous.”

Whatever the psychological outcomes, the study’s findings suggest that the Fukuda case definition identifies many people who might not in fact have the illness in question. The authors themselves write that, per their results, “including PEM as a polythetic criterion for CFS is inappropriate.” Yet they do not press that observation to its obvious end-point–which is that any case definition used to identify patients should require the presence of PEM. Instead, the authors call for research comparing how patients with and without severe PEM respond to psychological interventions.

So as far as I can tell, the main message of this paper is, or should be, that the Fukuda case definition is inadequate because many of those who meet it do not appear to experience PEM as a debilitating factor, if they experience it at all. Given that PEM is already viewed as the cardinal symptom of the illness, the logical conclusion is that such patients don’t have ME, despite having been diagnosed with CFS per Fukuda. As it reads, the study’s main finding seems to be that CFS patients with PEM need psychological intervention—when in fact what they really need most is effective medical treatments for their ME.





17 responses to “PEM Is Bad and So Is Fukuda, New Study Finds”

  1. Alicia Butcher Ehrhardt Avatar
    Alicia Butcher Ehrhardt

    Gobsmacked. Everyone I know who has ME/CFS (remember, there is NO actual diagnostic test) has PEM (hate the name – ‘malaise’ is so petty compared to the bone-weary exhaustion that can keep you from lifting your head).

    And everyone uses all the strategies they know – and learn – to live within the confines of a life-altering disease.

    To even suggest that we don’t want to get well, and are impeding our own recovery should be compared to mansplaining and gaslighting, strategies used by people who want to avoid admitting they are not able to figure out what’s physically wrong and how to fix it by pretending no help is needed. Or that we somehow DESERVE this.

    If I had the energy, I’d get mad. Madder. Terminator-level furious. But I do have to save a bit for breathing tomorrow.

  2. Lady Shambles Avatar
    Lady Shambles

    Oh good grief! Enough! Let’s fast forward through all this utter drivel and accept that at the moment the best criteria that could properly determine a cohort / diagnose in clinical terms ME (not synonym) is ICC and be done. Isn’t it curious that the most revealing science is coming from researchers who *do* use ICC to define their population? Let’s listen to them eh? Stop listening to all those who conflate ME with ‘CFS’ and SEID and Fukuda and Oxford and yada yada yada. If only out of Christmas bonhomie…let’s stop pretending that all these criteria sieve out the same disease…. they don’t. Let’s defer to ICC … it’s never going to be 100% perfect because it is a ‘description’ rather than ‘biomarker’… I guess we all understand that… but those of us with ICC who are very, very ill need help, and we don’t need this nonsense creeping into yet another decade!

  3. @MECFSNews Avatar

    A lot of psychology papers on ME/CFS are like this: some people happily fantasizing about all the ways in which we patients are supposedly deluded and making ourselves sick, based on findings that allow many different interpretations. They don’t seem to realize that they are creating and reinforcing a harmful narrative.

  4. Kate Avatar

    How utterly tiresome. And it’s odd Klimas is on the list of authors. Although she has been the co author of some papers that look at levels various stress markers and resulting severity….and there is one paper on the protective factor on illness severity post a natural disasters with psychosocial support, I’ve never seen something as outright as this. So….annoying.

  5. boolybooly Avatar

    Well done and thanks for a useful critique of more muddled thinking from unscientific psychologists. I hope the editors are made aware of your criticisms.

    It stands to reason diagnostic criteria used in experiments need to distinguish different conditions in order to gather meaningful data.

    Yet in ME this is still not being done effectively imho. None of the current criteria are specific for CFIDS as I know it i.e. PEM, sensory hypersensitivity, cognitive, autonomic, autoimmune symptoms, food intolerance, raised allergies and recurring virus. Yet Dr Paul Cheney would have identified this as classic CFIDS decades ago.

    The example I often use is Lymes, which is not what I have yet all the criteria would bundle Lymes patients in with people like me and most of them would include depression patients as well.

    We need to derive strict replicable criteria for distinct subgroups. Until we do, every attempt at replication will fail and research will continue to go round and round in circles in the gyre of uncertainty… until we do. Its the first step we have to take to establish a foundation for research, our precious efforts are wasted until that is done.

    So thanks and please keep telling it like it is.

    Merry Christmas! btw 🙂

  6. Sherrie Almes Avatar
    Sherrie Almes

    What is ICC?

  7. Seven Avatar

    From a very bad PEM patient, I have notice my PEM is related to my orthostatic intolerance, the worst my OI is, the worst the PEM. Also bacterial infections affect it.
    Now, periods and hormones have more to do with my OI getting worst, and therefore my PEM.
    I do get cranky when in pain (who doesn’t) but this theory is kinda absurd.
    So if I were to answer these questions, might be issues of feelings (more related to the period than the PEM itself!!) just a though.

  8. Art Vandelay Avatar
    Art Vandelay

    For the last time, I am not “tired” or “fatigued”. I AM SICK.

    PEM is not “a worsening of fatigue”, it is a worsening of ME/CFS symptoms. In my case, it is a worsening of brain fog, pain, nausea, and flu-like symptoms.

    Doctors and researchers need to start listening to patients.

  9. jimells Avatar

    The main message of the paper is that no one should pay the slightest attention to anything called “Journal of Psychosomatic Research”.

    When my head is pounding and light hurts and sound hurts and my shock index is greater than one and I can hardly drag myself to the toilet, the last thing I want or need is to have some nitwit with lots of letters after their name telling me I’m thinking the wrong thoughts.

    It’s disappointing to see Klimas’ name on this rubbish paper but not really a surprise. Klimas and others have been chasing cytokines and NK cells for years and years but have nothing important to show for it, like an effective treatment. There’s nothing wrong with having ideas that don’t work out. We need to know what doesn’t work. But please admit to it and move on, like the Norwegians have done with Rituximab.

  10. Wendy Boutilier Avatar
    Wendy Boutilier

    The Fukuda was written in the 1990’s for Chronic Fatigue Syndrome and studies or research using this broad based criteria is what the CFS Opportunist Trade thrive on. Broad based criteria equals higher prevalence equals more funding to produce more biased science.

    Use the Expert’s International Consensus Criteria “ICC 2011” for research and the IC Primer for diagnosis. This community has spent 35 yrs following corruption and placing the wrong people on the wrong pedestal.

  11. Guido Den Broeder Avatar
    Guido Den Broeder

    You keep repeating the same errors.

    Patients may satisfy CFS research criteria if and only if they have unexplained symptoms. You don’t satisfy CFS criteria if you have already been found to have ME.

    PEM is not a symptom of ME. PENE is. PENE is not a type of PEM. ME is not CFS, nor are CFS and ME in the same cluster of illnesses. CFS is not an illness, period.

  12. Lady Shambles Avatar
    Lady Shambles

    @Sherrie Almes

    To be simplistic this excellent advocacy resource might help to illustrate ICC in the first instance. Do look at their other material too.

  13. Andy Avatar

    Thank you again for taking on this line of thought, David.

    It does surprise me that these researchers seem unable to avoid the kind of errors of reporting on experimental findings that we are taught to guard against in the most basic of science classes.

    Equally bad is that other researchers who are peer reviewing the work seem unable to detect it either.

    Can we do a Crowd Funder at some point to send some of these people back to science school?

    The problem with Fukuda is something useful to come out of this paper even if, as you say, it is not the obvious conclusion that the authors are making. PEM should be an essential part of any diagnostic criteria.

  14. Steve Hawkins Avatar
    Steve Hawkins

    It’s the ‘Journal of psychosomatic research’.

    They only think it’s research. That way they can print anything!

    And: if exertion leads to malaise, and that malaise is part of the normal feelings one gets when damage is being repaired: feeling miserable about it is probably the body’s way of stopping you ‘running about on a broken leg’ or equivalent. These meddling ‘it’s in a psych magazine so it must be psych’ people, by trying to make patients think they are better than they are (which could be achieved easily with a dose of stimulants), they are inviting them to keep going until they have done irreparable damage (like the cyclists who used to drop dead on amphetamines, for example).

  15. Marion Barnett Avatar
    Marion Barnett

    Wouldn’t it be wonderful if researchers stopped frittering away precious resources on nonsense like this, coordinated their efforts, agreed a definitive set of diagnostic criteria, created a strategy for addressing the issue, and Got On With It ?…no, I don’t think so either, but a girl can dream. I’d settle for not being blamed for my own illness. Which doesn’t seem like too much to ask for…god knows, nobody would ever want to spend their days incapable of doing anything.

  16. Sue Klaus Avatar
    Sue Klaus

    Why is Klimas aligning with these people? An explanation is in order, and quick.

    Again, psychologists nudging out of their wheelhouse when their own strategies for depression keep failing. Why are we such a keen target for these people? Over 5000 studies covering ME being a physical illness, and still this abuse keeps happening.

    I can’t afford being this angry. Each time this happens it’s like an attack – on sick people, with few resources, with little to no help, and even fewer doctors educated. If you are not on the coasts or in Utah or Alabama you are screwed. Why does this keep happening?