PSYCHOTIC-LIKE EXPERIENCES IN CHILDREN AND ADOLESCENTS: CLINICAL AND NEUROBIOLOGICAL INSIGHTS INTO RISK FOR PSYCHOTIC DISORDERS

Abstract

This thesis examines psychotic-like experiences (PLEs) in children and adolescents, focusing on its assessment and neurobiological underpinnings to improve psychosis risk identification. The Chapter 2 systematic review and meta-analysis revealed that 17.3% of children and adolescents experience PLEs and are at a greater risk of developing psychosis in adulthood (OR = 3.80). Interview-based assessments identified individuals at greater risk than self-reports. The Chapter 4 population-based neuroimaging study using proton magnetic resonance spectroscopy found reduced myoinositol in the left hippocampus of adolescents with PLEs, but not in the prefrontal cortex nor in cannabis users. While no significant association was found between PLEs and cannabis use status, past-month cannabis exposure was positively associated with PLE severity and externalizing psychopathology. These findings highlight a role of hippocampal neuroinflammatory alterations in subclinical psychosis risk.