Bullying, Psychosis-Like Experiences, and Functional Network Connectivity in Adolescents

Bullying is an adverse childhood experience affecting up to one-third of the global population and linked to psychosis-like experiences (PLEs), which increase the risk of psychotic disorders. This study aimed to investigate the association between the severity and persistence of bullying and PLEs, including non-paranoid, hallucination-like experiences and their distress, and whether multiscale brain functional network connectivity (msFNC) mediates the pathway from bullying to PLEs. Methods: We used data from the ABCD Study, a large, multisite, population-based prospective cohort study following U.S. adolescents. We included adolescents with complete bullying and PLEs assessments at the 2- and 3-year follow-ups (T1: n=10,939, 47% females; T2: n=10,102). We examined the associations between bullying severity and temporal exposure and PLEs using linear mixed-effects models. In a 2-year resting-state fMRI subsample (n=5,280), we used a Neuromark framework to analyze whether msFNC statistically mediated the pathway from bullying to PLEs. Results: Higher PLEs were associated with the presence and severity of bullying (non-bullied vs. mild bullying: d=-0.24, CI:-0.30 to -0.19, p<0.0001; moderate vs. severe bullying: d=-0.62, CI:-0.69 to -0.56, p<0.0001). When bullying ceased, PLEs returned to non-bullied levels, whereas persistence over two years led to greater elevations (d=-0.36, CI:-0.43 to -0.29, p<0.0001), with similar patterns for non-paranoid and hallucination-like experiences and their distress. msFNC in paralimbic, default-mode, central executive, somatomotor, temporoparietal, insulotemporal, and frontal networks statistically mediated the association. Conclusions: Bullying is time- and dose-dependently associated with PLEs. msFNC may provide convergent evidence for distributed neurobiological correlates of the association between bullying exposure and PLEs.