The Institute of Medicine is a respected, American organization whose role is to provide ‘independent, objective advice on issues that affect people's lives’. They were given two main tasks here – ‘to define diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome, …, and to consider whether a new name for this disease is warranted’. The committee who wrote this report did just that. Their new name is ‘systemic exertion intolerance disease’ (SEID) and the new criteria require the following three symptoms: disabling fatigue for 6 months, post-exertional malaise, and unrefreshing sleep, with the addition of either ‘cognitive impairment’ or ‘orthostatic intolerance’.
How well did they do? Let's take the name first; Is CFS ‘systemic’? Well yes – and no. There are indeed replicated abnormalities of the endocrine, immune, autonomic, and cardiovascular systems in CFS, so that sounds pretty systemic. But that statement is equally true of depressive illness; should this therefore become ‘systemic emotion intolerance disease’? How about the term ‘exertion intolerance’? This is a characteristic feature of CFS. But, the authors argue for a change of name because they think the term chronic fatigue syndrome is ‘stigmatizing and trivializing’. So, how long it will take for being called ‘exertion intolerant’ to become pejorative? Calling CFS a disease implies that there is an established disease process. The evidence for this suggests multiple abnormalities in different systems – that are not generally associated with key features of the illness.
Do the new criteria hold more promise, particularly when we consider that the previous 20 versions were not empirically supported (Brurberg et al. Reference Brurberg, Fønhus, Larun, Flottorp and Malterud2014)? The authors are correct to emphasize the core symptoms of disabling fatigue, post-exertional malaise (or fatigue) and unrefreshing sleep, since a number of clinical studies confirm the frequency of these symptoms. Most clinicians would also include cognitive problems, although ‘impairments’ implies more objective signs of cognitive difficulties. But another ‘intolerance’ – orthostatic intolerance (OI) is questionable when good epidemiological studies find that objective evidence of OI occurs in relatively small minority of patients. The word ‘intolerance’ is also ambiguous in that the authors mean it to refer to both symptoms and signs. The final recommendation, which received early criticism, is to accept that SEID may be co-morbid with other conditions that can cause this cluster of symptoms, if treatment of the co-morbid condition does not relieve all the symptoms (Jason et al. Reference Jason, Sunnquist, Kot and Brown2015). This would mean that one could have a treatment-resistant depressive illness and co-morbid SEID at the same time. Jason et al. (Reference Jason, Sunnquist, Kot and Brown2015) found that 47% of a sample of patients with melancholic depression also met criteria for SEID (Jason et al. Reference Jason, Sunnquist, Kot and Brown2015). It is difficult to see how this helps either the patient or the doctor.
But perhaps the most unhelpful aspect of this report is its over-emphasis on the physical, with an almost complete absence of psychological and social aspects of the illness. We have a whole chapter reviewing the potential roles of immune, endocrine and infectious causes, but little if any mention of the potential roles of life events, stress, emotions, beliefs, and behaviour. This report took $1 million to produce, and the authors have missed a golden opportunity to integrate the findings of both mind and body to move us away from the sterile, dualistic understanding that still dominates this illness.
The report makes an unconvincing case for either a new name or new criteria. So is there an alternative approach? We should use existing, inclusive criteria, which can then be stratified by both common, allowable co-morbid conditions, such as chronic widespread pain, and by important associated abnormalities, such as low heart rate variability. This categorization would help to reveal those subgroups that make up this puzzling illness in order to show both their pathology and their personalized treatment response.
