Neural correlates of interoceptive fear in panic disorder: Abnormalities of gray matter volumes in the inferior parietal lobule and insula.

BACKGROUND

Panic disorder (PD) may emerge from an exaggerated misinterpretation of interoception due to somatic hypervigilance and interoceptive sensitivity, which play pivotal roles in anxiety-related traits. This study sought to identify the neural correlates of interoceptive fear and their relationship with clinical symptomatology and physical functionality in patients with PD relative to healthy controls (HCs) employing brain structural magnetic resonance imaging (MRI).

METHODS

This study enrolled 226 right-handed participants comprising 133 PD patients and 93 HCs. Interoceptive fear was measured utilizing the Albany Panic and Phobia Questionnaire alongside other clinical assessments that measured panic and anxiety symptoms and physical functioning. Gray matter volumes (GMVs) in T1-weighted MRI scans were analyzed using FreeSurfer software.

RESULTS

Patients with PD demonstrated significantly diminished GMVs within the extended fear network (EFN), including the inferior parietal lobule and insula, relative to HCs. In addition, among PD patients, high levels of interoceptive fear exhibited a significant correlation with decreased GMVs in the inferior parietal lobule and insula. Furthermore, the GMVs of the interoceptive fear-related inferior parietal lobule and insula were significantly related to higher panic and anxiety symptom severity and poorer physical functionality in patients with PD.

CONCLUSIONS

The current study provides novel evidence of interoceptive fear-related gray matter volume alterations in patients with PD. The GMVs of the interoceptive fear-related brain regions, which are components of the EFN, especially the inferior parietal lobule, may be associated with anxiety symptoms and physical functionality in patients with PD.