Previous magnetic resonance imaging (MRI) studies in patients with schizophrenia have reported increased brain gyrification in widespread cortical areas, which could reflect early developmental deviations. However, potential gyral anomalies in patients with schizotypal disorder have not been well documented. This MRI study explored brain gyrification in 46 patients with schizotypal disorder, 101 patients with schizophrenia, and 77 healthy controls. We collected T1-weighted magnetic resonance images from each participant and conducted group comparisons of local gyrification index (LGI) across the groups using FreeSurfer software. Compared with healthy controls, schizophrenia and schizotypal disorder patients commonly exhibited a significantly higher LGI in the bilateral prefrontal and left parietal cortices, possibly representing vulnerability to schizophrenia. Further, increased LGI in the right prefrontal and left occipital regions, which was preferentially observed in schizophrenia patients than in schizotypal disorder patients, might be related to the manifestation of florid psychosis.
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