Subcortical Brain Structures Among Maltreated Youth With High and Low Externalizing Problems

Alterations in brain structure following adversity show inconsistencies. Jointly considering maltreatment exposure alongside externalizing psychopathology may therefore prove helpful. However, few prospective studies currently follow up maltreated youth with high or low externalizing problems using neuroimaging assessments. A structural magnetic resonance imaging study was conducted using T1-weighted scans from 98 youth (MAge=14.76, SDAge=1.96; 51% girls) comparing participants with low (n=29) and high (n=29) maltreatment exposure to carefully matched non-maltreated controls (n=40). Comprehensive assessments of maltreatment history and psychopathology were ascertained across two waves, applying the Maltreatment Classification System alongside caregiver- and teacher-reported externalizing problems. Neuroimaging was conducted at the second wave. We found dose-dependent amygdala volume reductions following maltreatment and particularly abuse exposure, primarily driven by the basolateral subregion. Interaction analyses revealed lower amygdalar and hippocampal volumes in youth exposed to more vs. less extensive maltreatment, but merely among those with elevated externalizing problems. These findings highlight the value of the ecophenotype model for elucidating neural correlates of maltreatment and its sequelae.