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The size of the problem?
Functional symptom disorders—often termed ‘medically unexplained symptoms’—are being increasingly recognised as a major source of distress, confusion and—not least—cost. The 2016 Kings Fund report—‘Bringing Together Physical and Mental Health’—estimated that the National Health Service in England spends about 3 billion pounds per year on this group of conditions in adults and children.
Though published studies have revealed the importance of recognising and treating functional symptoms in adults, the literature in children is sparse. Raper and colleagues in this issue add significantly to our knowledge by reporting on a 20-year experience, in their centre, of children with functional neurological disorder (FND).1 FND, also known as conversion disorder, refers to a spectrum of neurological symptoms which have no established neurological cause and are assumed psychological in origin. Adult patients with FND are reported to have disappointing rates of recovery, but this long-term follow-up study highlights the emerging optimism for outcomes in children. Less than a quarter of those followed long term appeared to experience persistent severe functional symptoms in adult life.
Notably and unusually the reporting hospital has been accurately diagnosing and coding functional neurological symptoms reliably and routinely over the last 20 years. Precise recording and communication of the diagnosis of these patients seems to have become embedded in the culture of the setting for this study and is likely to be key to recovery. For progress to be made, this practice needs to be widely adopted nationally and internationally. The positive endorsement of a FND diagnosis means that it is recognised that these patients sit at the interface of physical and mental healthcare and are likely to need input from both disciplines. If there is inadequate or inaccurate recording of the incidence of functional symptom disorders, it is difficult to alert clinicians to the high likelihood of the disorder and the need to consider this in the differential diagnosis. It also becomes impossible to plan for, and meet the demand and need for, appropriate psychological and rehabilitation interventions.
Rates of functional symptoms are notoriously hard to pindown so the scale of the need for recognition and treatment is unknown. Population-based epidemiological studies of FND seem to produce unrealistically low rates, and these studies are difficult to do because of the need for a neurological examination in order to make the diagnosis. A recent large clinical series of adults with functional neurological symptoms notes that the changes in diagnostic classification and terminology make even clinic-based data collection difficult.2 Reported rates seem extraordinarily variable. For example, a study from specialist adult neurology clinics suggested that over 60% of patients had functional neurological symptoms.3 A clinical series in another tertiary paediatric neurology centre found that 12% of child neurology admissions were for medically unexplained neurological symptoms. Internationally, agreement about terminology and coding needs to improve in order to accumulate robust data regarding the rates of functional neurological symptoms.4
Classifying—lumping or splitting?
Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) published in 2013 and International Classification of Diseases 11th Revision (ICD-11) (published and due to be implemented in 2022) take somewhat contrasting approaches to the classification of FND. This may hamper rather than assist consistent data collection. DSM-5 has a broad umbrella category called ‘somatic symptom and related disorders’, which incorporates functional neurological disorders as a subcategory. This section helpfully reminds us that many patients have physiologically based medical diagnoses as well as functional symptoms; for example, epileptic and non-epileptic seizures may occur in the same patient. In contrast, ICD-11 labels FND, ‘dissociative neurological symptom disorder’, and places it in a separate category called ‘dissociative disorders’. Other somatic symptom disorders sit in a variety of categories, including a new one called ‘disorders of bodily distress or bodily experience’, which specifically excludes functional neurological symptoms.
This may be a ‘lumpers’ versus ‘splitters’ debate, where lumpers focus on similarities between conditions. In contrast, splitters focus on differences—resulting in the recognition of many categories of functional symptoms. Many clinicians see the benefits both diagnostically and therapeutically of including related somatic symptom disorders in one larger category (lumping), as this emphasises the commonalities in hypothesised mechanisms and presentations, and is economic in recognising that the most effective interventions are likely to be similar across these disorders.5 In children, individuals commonly have somatic symptoms in several body systems—so a more generic term might moderate the usually unhelpful tendency for children with functional neurological symptoms to accumulate multiple diagnoses. For example, a child with FND may also be having appointments in the gastroenterology department for unexplained abdominal pain or in rheumatology for aching joints. However, others argue strongly that terms such as ‘medically unexplained symptoms’, while usefully all encompassing, are unacceptable to clinicians and families, who like ‘explanations’. The authors of the current paper make a compelling case that a ‘positive’ diagnosis of FND—with its characteristic clinical features—opens up new, effective treatment options rather than making patients and families feel that nothing can be done.
Make a positive diagnosis, offer treatment and join up care
Rates of functional symptoms across many paediatric specialities are likely to be at their highest in specialist or tertiary centres, as these puzzling patients get referred onwards, and become concentrated in specialist settings. Clinicians and families may appear to seek relentlessly for a physical explanation, requesting and obtaining more opinions and more investigations. There is frequently a belief that families do not want psychological treatment—though it appears that this belief is often held more strongly by clinicians than by families. On the contrary, if the diagnosis of functional symptoms is made positively and empathically, with an emphasis on psychological treatments being the evidence-based treatment of choice—most families welcome the approach. What families seem to find most distressing is that their clinicians do not have a good knowledge and understanding of functional symptoms and their treatment and this promotes anxiety, lack of trust and poor engagement.6
The diagnosis involves both physical and mental health clinical working closely together. Although treatment is primarily psychological, clinical experience shows that both mental health clinicians and families appreciate the ongoing involvement of paediatricians—ideally in a collaborative and consultative capacity. The positive acknowledgement of a diagnosis of FND, and the encouraging outcomes in this long-term follow-up suggest that mental and physical healthcare is well integrated in the location of this study. This is far from the case in many settings, and authors such as Sharpe and Naylor7 rightly aspire to the ambition that mental healthcare should be not only as good as physical care but is also delivered as part of all health and care services. In the case of paediatric neurology clinics, this might include not only routine screening for emotional and behavioural disorders but ensuring that the possibility of functional symptoms is always considered. This means not waiting to refer to mental health services as a last resort when familiar causes have been ‘ruled-out’. It means recognising that almost every patient with a chronic health problem can be helped to optimise well-being and functioning with good communication and understanding of the impact of symptoms. For the group where a functional symptoms disorder is the main diagnosis, integration of psychological care has then already naturally become part of the package of intervention.
Funding Research at Great Ormond Street Hospital and UCL Institute of Child Health is made possible by the NIHR Great Ormond Street Hospital Biomedical Research Centre.
Competing interests None declared.
Patient consent for publication Not required.
Provenance and peer review Commissioned; internally peer reviewed.
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