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

A more positive brain-age gap (BAG) was associated with more externalizing problems in adolescents.

• BAG was calculated as the difference between model-predicted brain age and chronological age
• The association was found at the third timepoint (approximately age 14)
• No significant association was found between BAG and internalizing problems
• The sample included n=7658 participants (46% female) from the ABCD Study

Hypothesized associations between early life adversity (ELA) dimensions and brain-age-gap were not statistically significant.

• Four adversity dimensions were examined: threat, psychosocial deprivation, household instability, and socioeconomic stress
• Adversity was measured at baseline (approximately age 9-10)
• BAG was assessed at the second timepoint using structural neuroimaging data
• The null finding held across multiple adversity dimensions

Sex moderated the pathways between adversity and brain-age-gap, suggesting adversity differentially affects the pace of brain development in males and females.

• Sex moderation was tested across the pathways linking adversity, BAG, and mental health outcomes
• The sex-specific effects of adversity on BAG uniquely explained vulnerability to externalizing problems
• No equivalent sex-moderated pathways were reported for internalizing problems
• The authors describe these as 'sex-specific effects of adversity on adolescent development and mental health'

BAG did not significantly mediate the relationship between early life adversity and internalizing or externalizing problems at the overall sample level.

• Mediation analysis tested BAG as a mediator between baseline adversity and mental health outcomes at the third timepoint
• Data spanned three timepoints covering ages 9-14 years
• The mediation pathway was non-significant overall, though sex-moderated pathways were present
• Both internalizing and externalizing problems were assessed as outcomes

The study applied a normative brain-age predictive model trained on a large independent lifespan sample to the ABCD Study structural neuroimaging data.

• The ABCD Study sample comprised n=7658 participants, 46% female, ages approximately 9-14
• Structural neuroimaging data from the second timepoint were used to compute BAG
• The model was trained externally on a lifespan (not adolescent-only) normative sample
• This approach allowed estimation of brain maturity relative to chronological age norms