Brain Age Gap Associations with Externalising Behaviours in Youth: A Longitudinal Investigation in the Adolescent Brain Cognitive Development (ABCD) Cohort

A more positive brain age gap at ages 9–11 is linked to higher externalising symptoms at baseline in 10,516 ABCD adolescents, but the link weakens after sociodemographic adjustment.

• Why it matters: Externalising psychopathology emerges during early adolescence, yet brain age gap’s relationship to externalising symptoms and later trajectories is less established than for internalising behaviours.
• What they did: Brain age gap was computed from baseline cortical volume, area, and subcortical volume using an external validated prediction model, then tested with linear mixed-effects models against Child Behaviour Checklist externalising symptoms.
• The result: Baseline association was B[SE]=0.067[0.033], p=.042, and became non-significant after sociodemographic adjustment (B[SE]=0.056[0.033], p=.088); longitudinally, a brain age gap × age interaction persisted after adjustment (B[SE]=-0.007[0.003], p=.033), weakening across adolescence.