Functional symptoms in neurology: management

In this article we offer an approach to management of functional symptoms based on our own experience and on the evidence from other specialities (because the evidence from neurology is so slim). We also tackle some of the most difficult questions in this area. What causes functional symptoms? Does treatment really work? What about malingering?

We give two example cases adapted from real patients to illustrate our approach.

WHAT CAUSES FUNCTIONAL SYMPTOMS?

Table 1 is not comprehensive but it summarises a large literature on the suggested causes of functional symptoms. This is a question that has been approached from many angles—biological, cognitive, psychoanalytic, psychological, social, and historical. The factors shown have been found to be more common in patients with functional symptoms than in patients with similar symptoms clearly associated with disease pathology. Tables like this can help you to make a formulation of the aetiology of the patient’s symptoms rather than just a diagnosis. An important feature of the table is the recognition of biological as well as psychological and social factors in the production and persistence of functional symptoms.

Most of the factors in table 1 have also been associated with other types of functional somatic symptoms such as irritable bowel syndrome and chronic pain as well as with depression or anxiety. Consequently they should be regarded more as vulnerability factors for developing symptoms, than as specific explanations for why some patients develop certain symptoms such as unilateral paralysis and others have attacks that look like epilepsy. Recent functional imaging studies of patients with functional motor and sensory symptoms1 are beginning to offer biological clues (fig 1); they also challenge the idea that that such symptoms are “all in the mind”—they are in the brain too.2