ABSTRACT
Objective
Current concepts highlight the neurological and psychological heterogeneity of functional/dissociative seizures (FDS). However, it remains uncertain whether it is possible to distinguish between a limited number of subtypes of FDS disorders. We aimed to identify profiles of distinct FDS subtypes by cluster analysis of a multidimensional dataset without any a priori hypothesis.
Methods
We conducted an exploratory, prospective multicenter study of 169 patients with FDS. We collected biographical, trauma (childhood and adulthood traumatic experiences), semiological (seizure characteristics) and psychopathological data (psychiatric comorbidities, dissociation, and alexithymia) through psychiatric interviews and standardized scales. Clusters were identified by the Partitioning Around Medoids method. The similarity of patients was computed using Gower’s distance. The clusters were compared using ANOVA, chi-squared or Fisher’s exact tests.
Results
Three patient clusters were identified in this exploratory, hypothesis-generating study and named on the basis of their most prominent characteristics:
A “No/single trauma” group (31.4%) with more male patients, intellectual disabilities, non-hyperkinetic seizures, and a low level of psychopathology.
A “Cumulative lifetime traumas” group (42.6%) with clear female predominance, hyperkinetic seizures, relatively common comorbid epilepsy and high level of psychopathology.
A “Childhood traumas” group (26%) commonly with comorbid epilepsy, history of childhood sexual abuse (75%), and post-traumatic stress disorder, but high level of anxiety and dissociation.
Significance
While our cluster analysis was undertaken without any a priori hypothesis, the nature of the trauma history emerged as the most important differentiator between three common FDS disorder subtypes. This subdifferentiation of FDS disorders may facilitate the development of more specific therapeutic programs for each patient profile.
MAR