In my Twitter timeline recently, a few people have asked whether ‘ME’ (Myalgic Encephalomyelitis or Myalgic Encephalopathy) and ‘CFS’ (Chronic Fatigue Syndrome) are the same thing. There are also people I follow who are emphatic (sometimes aggressively) that these are not the same thing. For myself, I think there are differences, but these are not always made clear, and hence the confusion. But because of this confusion, inappropriate advice and treatment may be given.
This post gives my thoughts on this issue. I must point out that, although the definitions I use are real (references given later), the comments are my own interpretations of them; other people will have different views. In particular my ideas should not be taken as providing medical advice!
It is also possible that this post may add to some people’s confusion between ME and CFS, especially if you haven’t thought about it before; I apologise if this is the case, but the confusion exists anyway.
So, consider the following, which are described initially without using emotive names:
X is a definition of a clinical condition or disease, intended for diagnosis and the selection of appropriate treatment, that can be recognised by a pattern of symptoms, which range quite widely. They don’t all have to be present, although some do, and symptoms from certain categories need to be included. A key determining symptom is described as “post exertional neuroimmune exhaustion”, or PENE; put simply, this means that symptoms (including but not limited to fatigue) will tend to increase after any kind of activity, physical or mental. X excludes other conditions which may result in these symptoms, and this list includes primary psychiatric disorders such as clinical depression.
Z is a definition used mainly to select patients for research purposes. It emphasises ‘fatigue’ as the main symptom, notes that other symptoms may be present (but presumably don’t have to be), excludes other physical conditions but does not exclude depression or anxiety. A person who has X will fall within the definition of Z, as X is currently not formally recognised, but there are many more people covered by Z that do not have X.
Y is a bit of a hybrid between X and Z. It still has ‘fatigue’ as its main symptom, and requires at least one other symptom. So again, people with X will fall within the definition of Y, and people with Y will fall into the definition of Z; but these definitions widen each time.
The problem comes when a person with X is diagnosed under Y, and recommended treatments in Y which are those that have been found to be beneficial for most (but not all!) patients in research carried out under Z; however some of these are actually harmful for people with X.
This has come about because there is a tendency to regard the condition described under Z as a psychosomatic disorder, i.e. one where physical symptoms are caused by wrong attitudes and behaviours, and which can therefore be cured by addressing these. These include CBT (Cognitive Behaviour Therapy), which tries to get a person to change their thinking; and GET (Graded Exercise Therapy), which aims to restore a person’s physical functioning. However, given the importance of PENE in X, it is clear that GET in particular can actually be harmful, making a person worse.
An extreme case of this is happening in Denmark, where a young woman called Karina Hansen has been taken away from her parents and forced into what many believe to be inappropriate and harmful treatment.
OK, let’s remove the covers and identify our mystery guests.
X is the International Consensus Criteria for Myalgic Encephalomyelitis, published in 2011. It refers specifically to ME, and distances itself from the CFS label. It is a development of the 2003 Canadian Consensus Criteria, which used the hybrid term ME/CFS.
Y is the NICE guidance for CFS/ME, published in 2007, and which will be generally used for diagnosis within the UK. And because this refers mainly to CFS, this is often the label that will be given; or even Post-Viral Fatigue Syndrome (PFVS) if there is a viral infection that can be considered as triggering the condition.
Z is the Oxford Criteria for CFS, published in 1991.
I don’t know enough to go into the complexities of naming, but my simplistic understanding is that the term CFS was introduced as it was not clear whether ME really described what was going on inside the body. But another development was when the outbreak of ME at the Royal Free Hospital in 1955/6 was reviewed and dismissed as “mass hysteria”, thus discrediting a clinical definition of ME, and setting back research and the development of effective treatment.
I was formally diagnosed with PFVS in October 2006, although the symptoms began two years earlier. In discussion with doctors, I have always used ME, and been clear about the range of my symptoms, which (as I have since found for myself) do fall into the International Criteria (X).
I am generally fairly relaxed about terminology, and will use the hybrid term ME/CFS on the understanding that this is closer to X than Y. However, I do object to the use of CFS as a blanket term to cover people with X, especially when the underlying attitude and understanding of those who use CFS in this way is probably closer to Z. For example:
- “Chronic Fatigue Syndrome (also called Myalgic Encephalomyelitis)” seems to dismiss the complexity and severity of symptoms in X, and reinforces the view that it can be treated with CBT / GET.
- “Chronic Fatigue Syndrome (which patients prefer to call Myalgic Encephalomyelitis)” is even worse, and suggests that ME is simply not real. In the worst cases, this is used to suggest that patients want to believe there is a physiological disease, and that such belief prevents recovery.
In my opinion. a major example of this dismissive attitude is the FINE trial in the UK – Fatigue Intervention by Nurses Evaluation. I have made some comments on the materials used to train medical practitioners before their involvement in this trial in a couple of earlier blog posts (here and here). In particular these describe CFS using terms that treat it in terms of bad behaviour and wrong attitudes, saying in effect that “thinking that ‘exercise makes you worse’ will make you worse”. The materials include a definition of ME that actually says “exercise really does make you worse”, yet then gos on to blur and even ignore this distinction, suggesting that patients who “think” they have ME really have CFS as defined in a particular way.
Where does this leave us? As I mentioned before, this confusion (and in particular a lack of recognition of ME in terms suggested by X) results in people who have ME being diagnosed with CFS (or at best, and perhaps as a concession, CFS/ME), and being given treatment that may be inappropriate and even harmful.
What needs to happen? I would like health authorities across the world to recognise ME as a physiological condition that can be defined by something like X. This would mean the following:
- As a recognised condition, it would be excluded from CFS definitions such as Z. This means that results from previous research projects cannot be automatically assumed to be effective treatments for ME.
- A better understanding of the prevalence of ME (as opposed to the wider CFS) can be established.
- Research into how ME affects the body, and then what treatments will be effective, can proceed with a much clearer definition for patient selection.
- Patients who don’t have ME (X) but who do have CFS (Z) can also be identified and treated properly.
- We could drop the hybrid term ME/CFS, as people would know what we meant by ME.
It’s not clear whether this will happen; there are, for example, concerns over the current initiative in the USA to produce a new definition, as this may still end up closer to CFS. One more positive sign in the UK is the ME Association’s project to get copies of their “purple booklet” which describes ME into each GP surgery. And in the Netherland recently there was a mass demonstration under the banner “Erken ME” (recognise or acknowledge ME). These initiatives may move towards acceptance of a good clinical definition.
If I could have one wish granted for 2014, this would be it. In the meantime, I will continue to insist that ME (X) is not the same as CFS (Z), that CFS/ME (Y) is inadequate, and suggest that a simple diagnosis of CFS should be treated with caution, especially when there are lots of symptoms other than ‘fatigue’.