Exploring the Use of 'Functional' in Functional Neurological and Gastrointestinal Disorders

Abstract: Psychiatric diagnoses stand out as the most conceptually challenging within medicine. However, diagnostic constructs applying to conditions at the intersection between medicine and psychiatry, are even more troublesome. While terms like psychosomatic and psychogenic disorders have waned, functional disorder has (re-)gained popularity in the last decade.

This paper aims to analyze and contrast the use of the term 'functional' within two categories of functional disorders: functional neurological disorder (FND) and functional gastrointestinal disorders (FGID). The first segment of the paper provides a concise historical survey of the term 'functional' in medicine and psychiatry. The subsequent segment argues the fundamental differences in the term’s application in the two disorders mentioned. In the context of FND, 'functional' denotes an absence of any other neurological or medical disorder, thus operating as a negative concept. Conversely, 'functional' adheres to a robust and positive notion of gastro-intestinal function in FGID. This approach helps FGID escape the psychogenic versus somatogenic dichotomy, a challenge that has persisted in the diagnosis of FND (Alamrawy et al., 2023; Marotta et al., 2023).

In conclusion, the current work on the diagnoses of FND and FGID has practical implication. First, it highlights how different use of the term 'functional' impacts the classification of FND and FGID as a medical or a psychiatric disorder. Second, it helps clarify how this might impact patients' acceptability of the diagnosis. Lastly, it encourages a departure from mind-body dualism in favor of a more holistic view of health that acknowledges the intrinsic mind-body interconnectedness.