Health Technology Assessment: Behavioural Modification Interventions for Medically Unexplained Symptoms (MUS)


What are medically unexplained symptoms?

The term 'medically unexplained symptoms' (MUS), is sometimes used to refer to individuals who present to their GP with symptoms that persist over many weeks, but that cannot easily be explained even after numerous physical examinations and tests. These symptoms may also be referred to as 'functional' symptoms, and are likely to vary from individual to individual in terms of their number and severity. The term is also sometimes used to refer to poorly understood syndromes or 'clusters' of symptoms such as fibromyalgia, irritable bowel syndrome, or chronic fatigue syndrome. Use of the term MUS does not mean that the symptoms are not real, ‘made up’, or ‘all in the head’. MUS symptoms are real, can affect day-to-day functioning, and can be extremely distressing for the patient who is experiencing them. A diagnosis of MUS can be made using a range of diagnostic criteria or the clinician's expertise (e.g. a patient's GP). MUS are also a key feature of somatoform disorders, which must meet specific diagnostic criteria. There is wide variation in the use of the term ‘MUS’, and its use can be controversial. However this term is currently commonly used in the academic literature to refer to the above range of symptoms, and therefore we will use the term MUS to cover all of these variants in our evidence synthesis.

NHS Choices has more information on MUS

Why is this review needed?

MUS can be extremely distressing to the patient and can severely impact on their day-to-day functioning. MUS are very common and play some part in at least one in five GP consultations. This may place a large burden on the health services, with annual costs to the NHS estimated at £3.1 billion. This is due to increased GP visits and referrals for specialist tests or treatments in secondary care. For these reasons it is important to identify management strategies and treatments that may ease MUS symptoms and improve their quality of life for patients who experience MUS. Current treatments include pharmacological, psychological or physical interventions. Current evidence for the effectiveness of these treatments is mixed, with some reviews showing small to moderate improvements in physical symptoms and functioning, and some showing no effect. These differing results may be due to factors such as the way the intervention is delivered, e.g. by a specialist or GP, in a group or individually, or by the way the condition is defined, e.g. as specific syndromes or 'MUS' in general. The most common interventions delivered in primary care tend to be psychological interventions, such as cognitive behavioural therapy, behaviour therapies, or physical exercise therapies. Many of these therapies aim to change the behaviours of the individual that may be making their symptoms worse.

There are potential benefits to these therapies being delivered in primary care. Sometimes people with MUS do not want to be referred to psychological services, as they consider this stigmatising and feel that this means their symptoms are not being taken seriously. Therefore patients may be more ready to engage with such therapies if they are delivered within the primary care setting. There is currently no clear evidence as to whether these therapies are effective when they are delivered in primary care. However, it has been suggested that the doctor/therapist-patient relationship plays an important role in their effectiveness. Our project will undertake a systematic review of the evidence of the effectiveness of such treatments, and an analysis of whether they offer good value. We will also look at how acceptable they are to patients. We will use rigorous methodology to conduct searches for all the evidence relating to behavioural modification interventions for MUS that are delivered in a primary care or community based setting. We will extract information about whether the intervention improves symptoms, functioning and health-related quality of life, and what the barriers and facilitators to its effectiveness might be. We will then statistically analyse the data to obtain an overall effect. We will also conduct cost-effectiveness analyses to determine whether or not these interventions offer good value.