Longitudinal associations between greenspace exposure, structural brain development, and mental health and academic performance during early adolescence.

Background: Greenspace exposure is associated with positive mental health and academic outcomes. This preregistered longitudinal study examines whether the influence of greenspace exposure on structural brain development partially explains these associations.

Methods: We analyzed data from the Adolescent Brain Cognitive Development (ABCD) study (N=7102), to test the relationship between greenspace exposure at age 9-10 and brain structure two years later, as well as change over time. Additionally, we tested whether brain structural development statistically mediated the associations of greenspace exposure with mental health and academic performance.

Results: Greenspace exposure was associated with greater total surface area (SA) and cortical volume (CV), greater cortical thickness (CT) in temporal regions and the insula, lower thickness in the caudal middle frontal and superior frontal gyri, greater SA across several regions, and greater volume of the caudate nucleus, putamen, and nucleus accumbens. In analyses studying change in brain structure over time, higher greenspace exposure was associated with greater growth of total SA, lower average thickness reduction, and reduced total CV growth as well as changes at the regional level. We also found significant indirect effects of the association of greenspace exposure with academic performance and mental health through both total and regional cortical structure.

Conclusions: Greenspace exposure is linked to structural neurodevelopment, which is, in turn, associated with better mental health and academic achievement. Our findings underscore the importance of greenspace in supporting brain development and positive outcomes in children and adolescents.