MRI-based cortical gray/white matter contrast in young adults who endorse psychotic experiences or are at genetic risk for psychosis

Abstract

AbstractGroup-level differences in brain macrostructure between individuals at risk for psychosis and healthy controls have been well documented. However, while differences in cortical grey/white matter contrast (GWC), likely reflecting differences in myelin content, have been reported in clinical populations with psychotic disorders, no studies have explored GWC in individuals at elevated risk for psychosis. In this study, we explored whether brain microstructure, as measured with GWC, differs between young adults who endorsed psychotic experiences or genetic high risk for psychosis and healthy controls, and whether individual differences in GWC in at-risk individuals are associated with the number and psychotic experiences. The sample included individuals from two magnetic resonance imaging (MRI) substudies of the Avon Longitudinal Study of Parents and Children (ALSPAC): the psychotic experiences study and the schizophrenia recall-by-genotype study. The final sample included four groups of young adults 19-24 years old: individuals endorsing psychotic experiences (n=119) and health controls (n=117) and individuals with high (n=95) and low genetic risk for psychosis (n=95). Statistical analyses were performed using FSL’s Permutation Analysis of Linear Models (PALM), controlling for age and sex. The results showed no statistically significant differences in GWC between any of the groups and no significant associations between GWC and the number and experiences of psychotic experiences. In conclusion, the results indicate that GWC is not a sensitive neuroimaging marker for psychosis risk in young adults.