Structural alterations in early auditory cortex in borderline personality disorder with auditory verbal hallucinations.

Auditory Verbal Hallucinations (AVH) are not exclusive to schizophrenia but also occur in other psychiatric disorders, including Borderline Personality Disorder (BPD). While AVH in SZ has been extensively studied, their neurobiological underpinnings in BPD remain poorly understood. Preliminary evidence suggests structural anomalies in auditory regions among BPD patients experiencing AVH, indicating potential neuroanatomical vulnerabilities. This study examined structural brain differences in female BPD patients with (BPD-AVH n = 20) and without (BPD-nAVH n = 27) a lifetime history of AVH, as well as healthy controls (HC, n = 30), using high-resolution structural MRI. Cortical thickness (CTh), gyrification (CG), and gray matter volume (GMV) were assessed in frontotemporal regions implicated in auditory and speech processing, including the inferior frontal gyrus and superior, middle, and transverse temporal gyri. Region-of-interest (ROI) analyses were performed via CAT12, with supplementary segmentation of Heschl's gyrus using the TASH toolbox. Group comparisons were conducted using SPM12. Compared to both HC and BPD-nAVH, BPD-AVH patients showed significantly reduced CG in the right transverse temporal gyrus (rTTG), a region encompassing early auditory cortex. No significant group differences emerged in other ROI analyses, for GMV, CG or CTh. Reduced gyrification in the rTTG suggests aberrant cortical folding in early auditory regions among BPD patients with AVH. This may reflect disrupted neurodevelopmental processes that impair auditory signal encoding and internal vs. external sound source discrimination. These findings highlight the role of primary auditory cortex abnormalities in AVH and support transdiagnostic models emphasizing early sensory processing deficits.