Splitting FND: Differences in targeted therapies for functional movement disorders and functional seizures.

This article examines how functional neurological disorder (FND), historically called hysteria, is currently enacted in biomedical treatment discourse. Drawing on Annemarie Mol's concept of enactment, it explores how different therapeutic approaches produce divergent versions of the disorder across symptom clusters. Through a close reading of eleven narrative reviews published between 2016 and 2025, I analyse how targeted therapies for functional motor symptoms and functional seizures are justified, how they relate to diagnostic logic, and how they are shaped by historical assumptions. While both symptom clusters are diagnosed through rule-in criteria based on physical signs-rather than psychological aetiology-their treatment diverges substantially. Functional motor symptoms are increasingly addressed through FND-specific physiotherapy, grounded in neuroimaging studies and aimed at retraining automatic movement. Functional seizures, by contrast, are treated through adapted psychological therapies, particularly CBT-based interventions targeting emotion, stress, and behaviour. This divergence, I argue, enacts a therapeutic split that implicitly reflects a historical mind-body dualism. The disorder is neurologically diagnosed in both cases, yet treated physically in only one. Rarely problematised in the literature, this discrepancy has consequences for patients and FND's coherence as a diagnosis. This finding highlights a structural inconsistency in current clinical reasoning and raises questions about how FND might be managed without perpetuating outdated assumptions about emotion and the nature of somatic symptoms.