Beyond Distress and Resilience: Identification of Seven Distinct Emotional Phenotypes in Functional Neurological Disorder Through Large-Scale Digital Phenotyping

Abstract

Abstract

Objective: Functional Neurological Disorder (FND) has traditionally been understood through a binary emotional framework, distinguishing distressed from resilient patients. This study aimed to identify more nuanced emotional presentations using large-scale digital phenotyping data from a symptom-tracking application, emphasizing the importance of these insights for advancing clinical understanding. 
Method: The researchers analysed 10,556 emotion instances across 3,307 emotional logs from 1,032 FND patients using the NeuroLog mobile application [1]. While digital phenotyping offers real-time insights, limitations include potential selection bias and reliance on self-reporting, which may affect data validity. Co-occurrence clustering, hierarchical pattern analysis, and temporal transition modelling were employed to identify distinct emotional groupings with prevalence greater than 3%. 
Results: Seven distinct emotional phenotypes emerged: (1) Distress Cluster (40.2%), characterised by anxious-sad-frustrated presentations; (2) Shutdown Cluster (32.8%), marked by emotional numbing and low arousal; (3) Activation Cluster (33.6%), featuring paradoxical high energy with anxiety; (4) Anger Cluster (16.0%), showing frustration-anger spectrum presentations; (5) Social Isolation Cluster (16.3%), dominated by loneliness and grief; (6) Resilience Cluster (12.8%), representing positive emotional states; and (7) Ambivalent Cluster (9.5%), characterised by simultaneous positive and negative emotions. Critical findings included the Shutdown Cluster's previously unrecognised prevalence, the Anger Cluster's zero intervention utilisation, and differential recovery trajectories across phenotypes. 
Conclusions: FND emotional experience is multidimensional rather than bipolar. These findings have significant implications for personalised treatment approaches and suggest that current therapeutic models may inadequately address the heterogeneity of emotional presentations in FND, encouraging clinicians to consider more tailored interventions.