Joint Hypermobility Syndrome and Anxiety Disorder: Structural Brain Correlates

Abstract

Introduction

Joint hypermobility syndrome/Ehlers Danlos III (JHS/EDS III) is a common, connective tissue condition. This group is over-represented in panic/anxiety disorders and exhibits autonomic abnormalities and heightened interoceptive sensibility. Previous neuroimaging in healthy volunteers with hypermobility has observed differences in key emotional brain regions, notably amygdala and insula.

Aims and objective To explore, in a clinical population, the structural brain correlates underpinning the association between JHS/EDS III and anxiety.

Method

Seventy participants were divided into four experimental groups: (2 × 2 factor design: presence/absence of hypermobility; presence/absence of anxiety). Hypermobility was assessed using Brighton Criteria. All participants underwent brief tests of autonomic function and interoception. Structural images were obtained using a 1.5 T MRI scanner. Results are reported at whole brain uncorrected significance threshold of P < 0.001.

Results

Comparison of grey matter volume revealed increased insular volume in anxious patients with JHS/EDS-III compared to anxious patients without (Fig. 1A, B), correlating with initial peak heart rate on standing. Additionally, amygdala volume correlated with hypermobility score in anxious patients, but not in non-anxious individuals (Fig. 1C, D). Amygdala volume correlated with interoceptive accuracy.

Conclusions

This data implicates amygdala and insula as likely neural substrates mediating clinical relationships between hypermobility syndrome and anxiety, demonstrating the relevance of autonomic and interoceptive influences on this relationship. Further work hopes to explore functional and structural connectivity between these regions in JHS/EDS-III.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Figure 1 Structural neuroimaging of the relationship between joint hypermobility and anxiety. A. Insula structural differences in anxiety disorder in those with hypermobility syndrome compared to those without. B. Plot showing differences in insula volume. C. Amygdala structural differences, demonstrating significant interaction between anxiety status and degree of hypermobility. D. Plot showing interaction between anxiety on the relationship between amygdala volume and hypermobility source.