Hypermobility in patients with functional seizures: toward a pathobiological understanding of complex conditions

Background: Functional seizures (FS), otherwise known as psychogenic nonepileptic seizures (PNES), are a common symptom presenting to neurology and epilepsy clinics. There is a pressing need for further research to understand the neurobiology of FS to develop mechanistically targeted treatments. Joint hypermobility is an expression of variation in connective tissue structure along a spectrum, and it has received increasing attention in functional neurological disorders, but there is lack of evidence of its relevance in FS. Methods: In the present study, forty-two patients with FS and a non-clinical comparison group of 34 age/sex-matched controls were recruited. Joint hypermobility of all participants was quantified using the Beighton scale. Results: In our sample, 24 (57%) patients with FS, and 7 (21%) of the comparison group met criteria for joint hypermobility (p = 0.002). Our statistical model revealed that patients with FS showed a significant degree of hypermobility compared to the comparison group (odds ratio = 11.1; Confidence interval: 2.1–78.0, p = 0.008), even after controlling age, sex, anxiety, and depression. Conclusion: We found a significant association between FS and joint hypermobility, which was independent of anxiety and depression.