Childhood trauma and impulsivity in children with first-episode depression: mediation by left frontopolar thickness.

Childhood trauma is a key risk factor for adolescent depression, often associated with elevated levels of impulsivity. The Frontopolar Cortex (FPC), critical for executive control and impulse regulation, may be linked to this relationship, but its mechanistic role has not yet been fully elucidated. We examined 54 drug-naïve adolescents with first-episode Major Depressive Disorder (MDD) and 43 Healthy Controls (HCs), assessing trauma via the Childhood Trauma Questionnaire, and impulsivity via the Barratt Impulsiveness Scale. Structural Magnetic Resonance Imaging (MRI) was used to measure FPC thickness. Compared to HCs, MDD patients reported higher levels of trauma and impulsivity, with trauma exposure showing some variation across high and low impulsivity subgroups. The high-impulsivity subgroup exhibited significant left FPC thinning. Mediation analyses suggested that left FPC thickness might be associated with the relationship between childhood trauma and impulsivity, indicating a potential trauma-brain-behavior relationship. These results suggest that the FPC is a neural region involved in early adversity and impulsivity in depression. Clinically, targeting FPC-related circuits may potentially help mitigate impulsive behaviors and improve emotion regulation. Future research should explore the developmental mechanisms by which childhood trauma reshapes brain structure and influences behavioral outcomes in adolescent depression.Clinical trial number Not applicable.