The terminology is unsatisfactory.⁽²⁾ These symptoms are often referred to as ‘medically unexplained symptoms’. This usage has the advantage of describing the clinical problem without assumptions of aetiology, but it is unsatisfactory in that it wrongly implies that there is no medical explanation. Other generally used terms include somatization, somatoform symptoms, and functional overlay. It is perhaps most satisfactory to refer to functional symptoms and functional syndromes.

This chapter is concerned with functional symptoms whether or not they are associated with psychiatric disorder.

A traditional Western dualist view of aetiology as being either physical or psychological, continues to influence clinical practice and current psychiatric classifications (see Chapter 5.1). In western countries, this view has resulted in great problems in psychiatric and lay understanding, in taxonomy, and in the treatment of ‘unexplained’ symptoms. It has also caused bewilderment in cultures that do not share this dualist approach.

An increasingly widely held alternative view, for which there is compelling evidence, is that functional symptoms result from the interaction of physiological, pathological, and psychosocial variables.⁽²⁾ A primary bodily sensation or concern (Table 5.2.1.1) is then attributed or interpreted as being of sinister significance with resulting subjective symptoms, disability, and behavioural and emotional consequences. For example, awareness of normal heart rate increase due to excitement or anxiety can result in, on the one hand, panic and, on the other, worry about heart disease, restriction of daily activities, and repeated consultation to seek investigation
and reassurance. The role of these factors may vary over time during the course of any individual clinical problem.

There is considerable evidence on the ways in which psychological processes affect the interpretation of physical symptoms, whatever the underlying (major or minor) pathology or physiological processes. Cognitive-behavioural formulations emphasize the central significance of health anxiety and suggest that feedback of the physiological, cognitive, affective, and behavioural consequences of this anxiety can reinforce the physical symptoms as well as their effects on everyday life.

The process of interpretation of a bodily sensation or fear is affected by several sets of factors:

Once symptoms have developed they may be maintained by behavioural and psychological factors and also by the reactions of others. As with other forms of anxiety, neurobiological mechanisms may perpetuate and complicate the initial presentation.

Simple reassurance is often ineffective especially in those who, by reason of personality, are inclined to worry about their health. Misconceptions are frequently reinforced and maintained by the lack of any medical explanation for worrying symptoms or by ambiguous or contradictory advice.

The majority of functional symptoms in general populations are short lived and not associated with psychiatric disorder. There is now considerable evidence both from smaller local studies and international collaborative research that the more severe and disabling functional symptoms are associated with anxiety and depressive disorder, and that this relationship is strongest for those who have the greatest number of ‘unexplained’ symptoms. This is so for all ethnic groups and cultures studied.⁽¹⁾ There are also associations with the somatoform disorders as described below.