Dimensional adversity, brain-age, & mental health: Differences in male and female adolescents.

Early life adversity (ELA) has been linked to shifts in developmental pace. This study examined whether brain maturity during early adolescence was influenced by ELA, and whether it explained the relationship between ELA and mental health problems. A sample (n = 7658, 46 % female) from the Adolescent Brain and Cognitive Development (ABCD) Study was utilized, with data collected at three time points spanning 9-14 years of age. Exposure to threat, psychosocial deprivation, household instability, and socioeconomic stress were measured at baseline. A predictive model of normative brain development (brain age) trained on a large independent lifespan sample was applied to structural neuroimaging data from the second timepoint. Brain-age-gap (BAG) - the difference between model predicted brain age and chronological age - was tested as a mediator of adversity exposure and internalizing/externalizing problems at the third timepoint. A more positive BAG was associated with more externalizing problems, but hypothesized associations between adversity and BAG were not significant. Sex moderation of these pathways suggests adversity may differentially affect the pace of brain development for males and females, which uniquely explains vulnerability to externalizing problems. The findings highlight the importance of examining sex-specific effects of adversity on adolescent development and mental health.