Recognising and explaining functional neurological disorder

Correspondence to: J Stone [email protected].

What you need to know

• Functional neurological disorder (FND) is associated with considerable distress and disability. The symptoms are not faked

• Diagnose FND positively on the basis of typical clinical features. It is not a diagnosis of exclusion

• FND can be diagnosed and treated in presence of comorbid, pathophysiologically defined disease

• Psychological stressors are important risk factors but are neither necessary nor sufficient for the diagnosis

Functional disorders are conditions whose origin arises primarily from a disorder of nervous system functioning rather than clearly identifiable pathophysiological disease—such as irritable bowel syndrome, fibromyalgia, and functional neurological disorder (FND)—they are the second commonest reason for new neurology consultations.¹ FND is common in emergency settings,² stroke,³ and rehabilitation services.⁴ It causes considerable physical disability and distress, and often places an economic burden both on patients and health services.⁵ Many clinicians have had little formal clinical education on the assessment and management of these disorders, and patients are often not offered potentially effective treatments.

In practice, FND should be diagnosed by someone with specific expertise in the diagnosis of neurological conditions. Our recommendation is to refer all patients with a suspected diagnosis of FND to secondary care. However, the diagnosis may be raised as a possibility with the patient in primary care, and knowledge of how the diagnosis is confirmed greatly aids subsequent management.

In this article we offer evidence based advice to generalists on how to recognise FND, based on clinical diagnostic and prognostic studies. Although the focus of this paper is on recognising FND, we have included a short box on management to make readers aware that there are good treatments available for FND and that some patients can get better.

Sources and selection criteria

We conducted a PubMed search of evidence for diagnosis of functional neurological disorder (FND) until June 2020, especially systematic reviews.¹⁴³⁰³¹ We also relied on author research paper archives, and a recent international comprehensive textbook on FND (JS and AC were co-editors).³² The article was reviewed and improved by representatives from five patient organisations: FND Hope, FND Hope UK, FND Action, FND Dimensions, and FND Friends.

What is functional neurological disorder?

FND describes a disorder of the voluntary motor...