The ‘medically unexplained symptoms’ syndrome concept and the cognitive-behavioural treatment model, by Michael J Scott , Joan S Crawford , Keith J Geraghty , David F Marks in Journal of Health Psychology Sep 2021 [doi:10.1177/13591053211038042]
The American Psychiatric Association’s, 2013 DSM-5 abandoned the use of the term ‘medically unexplained symptoms’ for non-neurological disorders. In the UK, treatments for various medical illnesses with unexplained aetiology, such as chronic fatigue syndrome, irritable bowel syndrome and fibromyalgia, continue to fall under an MUS umbrella with cognitive behavioural therapy promoted as a primary therapeutic approach.
In this editorial, we comment on whether the MUS concept is a viable diagnostic term, the credibility of the cognitive-behavioural MUS treatment model, the necessity of practitioner training and the validity of evidence of effectiveness in routine practice.
As the MUS diagnostic category is alleged to include up to one-third of all patients seen in primary care on a regular basis (Nimnuan et al., 2001), the scale of the artificially created ‘syndrome’ highlights the absurdity of such a conceptualisation.
Maes and Twisk (2010) provide a predominantly biological model to help explain chronic fatigue syndrome, rescuing it from the ‘unexplained’ category. Their model explains readily why immunological and endocrinological variables better predict outcome in CFS than psychological variables. By contrast, in the Harvey and Wessely (2009) model of CFS there is no specification of any key and lock mechanism that is, what precipitant, acting on which predisposing factor would usher in the said debility, nor which perpetuating factor would be pertinent to which key-lock combination.
A recurring theme among practitioners applying the CBM is the claim that dysfunctional illness beliefs (e.g. that ‘symptoms are the result of a virus’) are causally linked to deconditioning and a poor prognosis (e.g. Wessely et al., 1991). Attempting to induce patients into cognitive behaviour therapy (CBT) to change the way they are alleged to habitually think has not proved a successful strategy, as the revised NICE (2020) guidance has concluded.
The MUS concept can no longer be accepted as a viable diagnostic term. The credibility of the cognitive-behavioural MUS treatment model has reached a nadir and can be given only an auxiliary role in treatment. An urgent necessity to provide practitioner training has been identified and the need for greater awareness of the misleading nature of poor quality evidence for effectiveness of the CBT approach in routine practice.