Schizophrenia is a severely disabling mental disorder with largely unknown underlying mechanisms. Although fully developed psychosis is typically diagnosed in early adulthood, symptoms often begin manifesting in a sub-clinical state during adolescence. This thesis investigates the neurodevelopmental underpinnings of psychosis vulnerability, particularly through the lens of 22q11.2 Deletion Syndrome (22q11DS). By developing and applying advanced brain functional imaging techniques, specifically for resting-state functional MRI (rs-fMRI), this work explores the maturation of brain circuits and their association with psychosis.

In summary, our findings support the notion of aberrant brain developmental processes, particularly in subcortical structures, leading to psychosis. We show that the methodology of rs-fMRI can be used to extract valuable information with regards to clinically relevant alterations in the brain. Furthermore, we provide the first evidence of cerebrovascular functional abnormalities in patients with 22q11DS, highlighting the need for further investigation.