Defying dualism in functional neurological disorder … again: response to Scamvougeras and Castle

This commentary responds to an article by Anton Scamvougeras and David Castle arguing that contemporary accounts of Functional Neurological Disorder (FND) overemphasise neurobiology and that the disorder should be understood primarily as a psychiatric condition. There are areas of agreement, including the need for a biopsychosocial model and acknowledgement that some academic and public discourse about FND has minimised psychological factors. However, proposed distinctions between neurological and psychiatric disorders based on the presence or absence of pathology are conceptually unstable. Many neurological conditions, such as Parkinson's disease and epilepsy, are intrinsically neuropsychiatric, while others, including migraine and Tourette syndrome, lack pathology on standard investigations. FND also raises another fundamental question: whether a neurologist's role is to seek pathological disease or to diagnose and manage neurological symptoms. Claims that current literature promotes a purely biological model are overstated. The proposal that the psychiatric level is the best way in which to understand FND promotes the idea that psychiatric factors are universally explanatory. Instead, the evidence supports a multi-level understanding of the aetiology and mechanisms of FND symptoms, including how they arise from altered brain networks. A non-dualistic framework, as seen, for example, in chronic nociplastic pain, allows a psychiatric perspective to sit alongside a neurobiological one, without one having to dominate the other.