Exploring the relationship between hallucination proneness and brain morphology.

Background: Hallucinations, including both auditory and visual forms, are often associated with alterations in brain structure, particularly in specific language-related cortical areas. Existing models propose different frameworks for understanding the relationship between brain volume and hallucination proneness, but practical evidence supporting these models is limited.

Methods: This study investigated the relationship between hallucination proneness and brain volume in language-related cortical regions, specifically the superior temporal gyrus and Broca's area. A total of 68 participants, primarily university students, completed the Launay-Slade Hallucination Scale (LSHS) to assess hallucination proneness for both auditory and visual experiences. Structural MRI scans were used to measure brain volume in the targeted regions.

Results: The results indicated significant positive correlations between LSHS scores and brain volume in the superior temporal gyrus and Broca's area regions previously linked to volume reductions in patients with clinically diagnosed hallucinations. Participants reporting high hallucination proneness for both auditory and visual hallucinations exhibited higher brain volumes in these language areas compared to those experiencing hallucinations rarely or never.

Conclusions: These findings challenge existing models by suggesting that higher brain volumes in language-related cortical areas may be associated with increased proneness to both auditory and visual hallucinations in non-clinical populations. This contrasts with the volume reductions seen in patients with clinical hallucinations and highlights the need for further research into the complex interplay between brain structure and hallucinatory experiences.