Neuroanatomical Correlates of Auditory Hallucinations in Schizophrenia: A Structural MRI Morphometry Study

BACKGROUND/AIMS: Schizophrenia is a complex neuropsychiatric disorder marked by diverse structural brain abnormalities and clinical heterogeneity. Auditory verbal hallucinations (AVH), a hallmark symptom of the disorder, are thought to involve disruptions in limbic, paralimbic, and cortical circuits. While volumetric and cortical thickness alterations have been extensively investigated, the interplay between brain morphometry, symptom severity, and demographic variables remains incompletely understood. This study aims to investigate differences in cortical and subcortical structures among patients with schizophrenia who do and do not experience auditory hallucinations, and healthy control participants. MATERIALS AND METHODS: Structural magnetic resonance imaging data were derived from the publicly accessible OpenNeuro repository (accession: ds004302), which contains pre-existing T1-weighted images acquired from adults with schizophrenia and healthy controls under standardized protocols. The analytic sample consisted of 46 patients with schizophrenia (23 with AVH and 23 without) and 41 age- and sex-matched healthy controls, all aged 18-65 years. High-resolution images were processed using the vol2Brain automated segmentation pipeline to extract cortical thickness and subcortical volumetric metrics across more than one hundred anatomically defined regions. Group differences were assessed using Mann-Whitney U and independent-samples t-tests, and associations between structural measures and clinical or demographic variables (including hallucination severity, age, sex, and intelligence quotient) were examined using Pearson’s correlations. RESULTS: Compared to healthy controls, schizophrenia patients exhibited widespread reductions in regional brain volumes, particularly in temporal and thalamic regions. Sex-based analyses revealed significantly larger global and regional volumes in males across both the full sample and the schizophrenia subgroup. Notably, greater AVH severity was associated with lower volumes of the basal forebrain and the posterior cingulate cortex, and with increased volume of the superior frontal gyrus. Cortical thickness differences were more limited, but revealed age-related reductions and significant associations with symptom severity. Correlation analyses highlighted robust associations between age, sex, and key neuroimaging metrics, underlining the importance of demographic moderators. CONCLUSION: The findings reinforce the notion that schizophrenia, and especially AVH symptomatology, is characterized by specific and clinically meaningful neuroanatomical alterations. Volumetric changes in limbic and frontal circuits appear particularly sensitive to both symptom severity and demographic context, supporting their role in AVH pathophysiology and the broader neurobiology of schizophrenia.