The prevalence of post-traumatic stress disorder in functional / dissociative seizures: A systematic review and...

Individual studies have highlighted elevated rates of post-traumatic stress disorder (PTSD) in cohorts of people with functional / dissociative seizures; however, prevalence estimates vary and the strength of the association between FDS and traumatic symptoms is contested. In the current review, we meta-analyse studies reporting the co-occurrence rate of PTSD and FDS before exploring sources of heterogeneity through moderator analysis.

Systematic searches were performed in July 2025 in Scopus, MEDLINE and PsycInfo. We included studies reporting the proportion of adult FDS cohorts with clinically diagnosed or probable PTSD (e.g., passing thresholds on PTSD screening instruments). The Joanna Briggs Institute Quality Appraisal Tool was used to assess the quality of included studies.

The random effects meta-analysis included 34 studies representing data from 31,711 individuals with FDS. The pooled effect size (PTSD and FDS co-occurrence) was 37.7% (95% CI = 30.0 - 45.6%). Between-study heterogeneity was partially explained by sample frame (clinical or non-clinical settings), risk of bias, and the method used for identifying PTSD. Studies of higher quality reported higher rates of comorbidity.

Approximately one-third of those with FDS had been diagnosed with PTSD or were exhibiting symptoms likely to meet the diagnostic criteria for PTSD. Although this finding is clinically significant, most individuals with FDS do not meet this criterion, indicating PTSD is not a universal feature in the FDS population. Future meta-analyses would benefit from utilising individual patient data to enhance moderator interpretation.