Psychosocial correlates of seizure severity in adults with functional/dissociative seizures (FDS): a systematic review

Objectives

The severity of functional / dissociative seizures (FDS) is commonly explored in the literature, with a recent review identifying it as the second most frequently used seizure-specific measure in FDS outcome studies. In this review, we examine available evidence for factors associated with FDS severity and discuss how this concept has been measured.

Methods

A systematic search was performed in July 2023 (repeated in April 2024) across four databases (PsycInfo, MEDLINE, CINAHL and Cochrane Reviews). Eligible studies were subjected to quality assessment using an adapted version of the Appraisal Tool for Cross-Sectional Studies (AXIS) or the CASP Cohort Study Checklist. Findings were narratively synthesised.

Results

Twelve articles met the inclusion criteria; eleven cross-sectional and one cohort study. Eleven different methodological approaches capturing FDS severity were identified. No studies were primarily designed to explore correlates of FDS severity. Correlates were grouped thematically and ordered based on the number of studies contributing to each theme. Weak to moderate correlations were found within the domains of trauma, mental health, emotional processes, relational, illness perception, symptom attribution, and demographics.

Conclusions

In the absence of validated measures of FDS severity, researchers have used a variety of tools to capture this clinical feature. The range of correlations found for different measures provide initial support for the conceptual validity of FDS severity measures as a treatment outcome and a rationale for the development and validation of an FDS-specific seizure severity measure.