Effects of genetic liability to psychosis proneness and psychosis proneness on functional connectivity of the salience network

The effect of psychosis proneness, a psychometrically defined index of subclinical psychosis, has limited research on its effect on brain connectivity in healthy populations. In addition, functional connectivity research in psychosis proneness mainly focuses on brain networks such as the default-mode network (DMN) and the central executive network (CEN) but not on the salience network (SN). On a similar note, research on genetic susceptibility to psychosis in healthy populations and the combinatory analysis between brain connectivity and genetic liability have not been explored thoroughly. This thesis assessed the relationship between psychosis proneness and genetic liability to psychosis to functional connectivity of the salience network. Seventy-two pairs of twins, siblings, and triplets were included in the analysis for genetic liability and functional connectivity. Participants’ psychosis proneness was assessed via the Community Assessment of Psychic Experience (CAPE-42) questionnaire, and genetic liability scores (PRS-SCZ) were calculated through PLINK and PRSIce-2 software. Global patterns of connectivity, seed-based connectivity, and network topology of the salience network were examined. The findings have revealed that the connectivity levels within the salience network differed in individuals with high psychosis proneness com- pared to individuals with low psychosis proneness. Further analysis has shown that PRS-SCZ did not show a significant difference between high and low psy- chosis proneness groups. The results show that connectivity levels in the salience network differ in individuals with psychometrically defined psychosis proneness. These results were not explained by differences in genetic loading among the participants.