Bullying and Early Brain Development: A Longitudinal Structural Magnetic Resonance Imaging Study from Adolescence to Early Adulthood

To explore this, we conducted the largest structural MRI analysis to date (n=2094, including 1009 females), across three time points from the IMAGEN study, tracking region-specific brain volume trajectories from adolescence to early adulthood using a data-driven approach. Generally, experienced bullying showed increased subcortical volumes in the putamen (beta=0.12), caudate (beta=0.06), accumbens (beta=0.06), amygdala (beta=0.07), hippocampus (beta=0.06), paired with decreased cerebellar (beta=-0.10), entorhinal, (beta=-0.12), and insula (beta=-0.11) volumes. Females exhibited more volumetric changes in emotional processing areas whereas males had more changes in motor and sensory regions. These findings point to widespread associations between bullying victimization and brain development, offering a potential neurobiological framework to explain the emotional and behavioral difficulties observed. Importantly, this study emphasizes the need for a sex-sensitive approach in future research and interventions related to bullying.