Children who grow up in disadvantaged neighborhoods show faster declines in key measures of brain development during adolescence compared to peers from higher-opportunity areas, according to a new study published in the journal Cerebral Cortex.
The brain undergoes dramatic changes during adolescence. Two of the most carefully studied metrics are cortical thickness (how thick the outer layer of the brain is) and cortical surface area (the total surface space that outer layer covers). Both typically decrease during the teenage years as the brain refines itself and becomes more efficient.
Scientists have known that children from different socioeconomic backgrounds show differences in these brain measures, but most previous research has focused on family-level factors like parental income. Less attention has been paid to the broader neighborhood environment in which a child grows up, including both its positive and negative attributes.
Led by Chloe Carrick of King’s College London, the research team analyzed brain imaging data collected at three time points—at approximately ages 10, 12, and 14—from 11,639 children (48% female) enrolled in the Adolescent Brain Cognitive Development (ABCD) study in the United States.
Neighborhood disadvantage was measured using the Area Deprivation Index, which factors in poverty levels, employment, and housing quality. Meanwhile, neighborhood educational and health/environmental opportunities were assessed using the Childhood Opportunity Index. The researchers used statistical models to track individual differences in how each child’s brain changed over time, controlling for family income, biological sex, and the type of MRI brain scanner used.
The study found that children who lived in more disadvantaged neighborhoods at ages 9–10 had lower cortical thickness and surface area to begin with, and they experienced faster rates of decline in these measures as they moved through adolescence.
In contrast, children from neighborhoods with greater educational, health, and environmental opportunities showed higher starting levels of both brain measures, and their brains changed more slowly over the same period.
These associations held up even after accounting for the family’s income level, suggesting that the neighborhood environment contributes something beyond what the family’s financial situation alone can explain. Importantly, when analyzing the trajectory of the children’s brain development, the researchers did not find distinct, separate subgroups of children. Instead, the differences were spread continuously across the population, with no sharp dividing lines between groups.
The authors suggest that “it is possible that growing up in a disadvantaged neighborhood increases exposure to stressful stimuli, including community violence or environmental pollutants,” which may cause the brain to mature faster as an adaptive survival response. Conversely, living in a resource-rich neighborhood may support a slower, more extended period of brain development, potentially prolonging the period of neuroplasticity and allowing more time for the brain to build complex connections.
However, the researchers note some limitations. The effect sizes observed were small, meaning that while the patterns are real and statistically robust given the massive sample size, they explain only a limited portion of the variation between individuals. Furthermore, when the researchers ran a sensitivity analysis to control for overall brain size, the link between neighborhood disadvantage and the *pace* of cortical thinning was no longer statistically significant, suggesting some of these specific relationships may be driven by differences in global brain size.
The study, “Individual differences in adolescent cortical development are associated with neighborhood characteristics: Longitudinal findings from the ABCD study,” was authored by Chloe Carrick, Divyangana Rakesh, Lea Michel, Kathryn Bates, and Delia Fuhrmann.