A Social Gradient of Cortical Thickness in Adolescence: Relationships With Neighborhood Socioeconomic Disadvantage, Family Socioeconomic Status, and Depressive Symptoms.

ABSTRACT

BACKGROUND: Mental and physical health are affected by family and neighborhood socioeconomic status (SES). Accelerated maturation 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 putative markers of brain maturation in adolescents. METHODS: In 120 adolescents 13 to 18 years of age, we examined family and neighborhood SES in relation to cortical thickness adjusted for age. We also examined whether cortical thickness was related to depressive symptoms and explored regions of interest. RESULTS: Controlling for age, neighborhood socioeconomic disadvantage was associated with a thinner cortex in the left hemisphere (standardized ß = -0.20), which was related to more severe depressive symptoms (standardized ß = -0.33). Family SES was not significantly associated with age-adjusted mean cortical thickness in either hemisphere after controlling for relevant covariates. In exploratory, covariate-adjusted analyses of cortical thickness at the regional level, neighborhood socioeconomic disadvantage was associated with reduced cortical thickness in the left superior frontal gyrus (standardized ß = -0.27), fusiform gyrus (standardized ß = -0.20), and insula (standardized ß = -0.21), whereas family SES was positively associated with cortical thickness in the right lateral and right medial orbitofrontal cortex (standardized ß = 0.21 and standardized ß = 0.19, respectively) and left transverse temporal gyrus (standardized ß = 0.22). CONCLUSIONS: Our findings provide evidence for a social gradient of cortical thickness during adolescence. Adolescents living in less advantaged community or family contexts appear to have a thinner cortex according to global and regional measures. Reduced cortical thickness in the left hemisphere may indicate increased risk for depression in adolescence.