Cognitive correlates of psychopathology in Functional/Dissociative Seizures and non-lesional epilepsy: an exploratory study

Objective: To explore the relationship between cognitive functioning and psychopathological features in Functional/Dissociative Seizures (FDS), and test whether this differs from that observed in epilepsy. Methods: We recruited a cross-sectional sample of adults (age > 18) with a diagnosis of non-lesional epilepsy or FDS between January 2021 and July 2022. Participants completed a series of psychiatric questionnaires and neuropsychological measures. Spearmans Correlation Coefficient was computed between each of the psychiatric and cognitive measures in each group. Fishers Z test of significance for independent correlation coefficients then tested the significance of the difference between correlation coefficients for the two groups. Results: There were no group differences in neuropsychological test scores. However, people with FDS reported higher seizure severity, depression levels, number of medically unexplained somatic symptoms, and exposure to traumatic events compared to epilepsy. Results of the Fishers Z-test revealed significant differences in correlation coefficients between groups in two instances. First, in the association between the number of traumatic experiences and cognitive switching (z = 2.77, p = 0.006); the number of traumatic experiences were positively associated with cognitive switching in epilepsy but showed a non-significant negative trend in FDS. Secondly, in the association between vocabulary abilities and the number of medically unexplained symptoms (z = -2.71; p = 0.007); higher vocabulary ability was associated with fewer somatic symptoms in epilepsy, while no such correlation was observed in FDS. Significance: This study provides preliminary evidence for the complex interplay between cognitive functioning and psychopathology in FDS and epilepsy. Neurocognitive functioning such as vocabulary abilities or attentional switching may play a role in the expression or maintenance of pathological features of FDS. ### Competing Interest Statement Allan H. Young: Employed by King s College London; Honorary Consultant SLaM (NHS UK) Deputy Editor, BJPsych Open. Received honoraria for attending advisory boards and presenting talks at meetings organised by LivaNova. Principal Investigator in the Restore-Life VNS registry study funded by LivaNova. The remaining authors have no conflicts of interest. ### Funding Statement This work was supported by the Bergqvist Charitable Trust through the Psychiatry Research Trust as a PhD scholarship to Irene Faiman. Professor Young s independent research is funded by the National Institute for Health Research (NIHR) Biomedical Research Centre at South London and Maudsley NHS Foundation Trust and King s College London. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the London Queen Square Research Ethics Committee (REC: 20/LO/ 0784, IRAS ID: 265164, 28/09/2021). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Anonymised data are available upon request for collaborative purposes.