Increased Occipital Gyrification and Development of Psychotic Disorders in Individuals With an At-Risk Mental State: A Multicenter Study.

BACKGROUND: Anomalies of brain gyrification have been reported in schizophrenia, possibly reflecting its neurodevelopmental pathology. However, it remains elusive whether individuals at risk for psychotic disorders exhibit deviated gyrification patterns, and whether such findings, if present, are predictive of transition to psychotic disorders.

METHODS: This multicenter magnetic resonance imaging study investigated brain gyrification and its relationship to later transition to psychotic disorders in a large sample of at-risk mental state (ARMS) individuals. T1-weighted magnetic resonance imaging scans were obtained from 104 ARMS individuals, of whom 21 (20.2%) exhibited the transition to psychotic disorders during clinical follow-up (mean = 4.9 years, SD = 2.6 years), and 104 healthy control subjects at 4 different sites. The local gyrification index (LGI) of the entire cortex was compared across the groups using FreeSurfer software.

RESULTS: Compared with the control subjects, ARMS individuals showed a significantly higher LGI in widespread cortical areas, including the bilateral frontal, temporal, parietal, and occipital regions, which was partly associated with prodromal symptomatology. ARMS individuals who exhibited the transition to psychotic disorders showed a significantly higher LGI in the left occipital region compared with individuals without transition.

CONCLUSIONS: These findings suggested that increased LGI in diverse cortical regions might represent vulnerability to psychopathology, while increased LGI in the left occipital cortex might be related to subsequent manifestation of florid psychotic disorders as a possible surrogate marker.