A Social Gradient of Cortical Thickness Relative to Age in Adolescence: Relations Among Neighborhood Socioeconomic Disadvantage, Advanced Cortical Thinning, and Depressive Symptoms

Background: Mental and physical health are affected by family and neighborhood socioeconomic status (SES). Accelerated biological aging in the context of lower SES is one mechanism that might contribute to underlying health disparities; few studies, however, have considered neighborhood SES in relation to neural markers of biological aging in adolescents. Methods: In 120 adolescents 13-18 years of age, we examined family and neighborhood SES in relation to biological aging in the brain, indexed by cortical thickness relative to chronological age. We also examined whether advanced cortical thinning relative to age was related to depressive symptoms and explored regions of interest.Results: Neighborhood socioeconomic disadvantage was uniquely associated with advanced cortical thinning in the left hemisphere (=-.20), which was related to more severe depressive symptoms (=-.33). In contrast, family income-to-needs was not significantly associated with cortical thickness age after controlling for relevant covariates. In exploratory, covariate-adjusted analyses of cortical thickness relative to age at the regional level, neighborhood socioeconomic disadvantage was associated with advanced cortical thinning in the left superior frontal gyrus (=-.27), fusiform gyrus (=-.20), and insula (=-.21). Of these regions, only advanced cortical thinning in the left superior frontal gyrus was associated with more severe depressive symptoms (=-.18). Conclusion: Our findings provide evidence for a social gradient of accelerated biological aging at the neural level during adolescence. Adolescents living in less advantaged communities have a thinner left hemisphere cortex than expected given their chronological age. Advanced cortical thinning may increase risk for depression in adolescence.