Environmental Determinants of Aggression in Adolescents: Role of Urban Neighborhood Greenspace

Abstract

Objective: Neighborhood greenspace improves mental health of urban-dwelling populations, but its putative neurobehavioral benefits in adolescents remain unclear. We conducted a prospective study on urban-dwelling adolescents to examine the association between greenspace in residential neighborhood and aggressive behaviors.

Method: Participants (n = 1,287) of the Risk Factors for Antisocial Behavior Study, a multi-ethnic cohort of twins and triplets born in 1990 to 1995 and living in Southern California, were examined in 2000 to 2012 (aged 9-18 years) with repeated assessments of their aggressive behaviors by the parent-reported Child Behavior Checklist. Normalized Difference Vegetation Index (NDVI) derived from satellite imagery was used as a proxy for residential neighborhood greenspace aggregated over various spatiotemporal scales before each assessment. Multilevel mixed-effects models were used to estimate the effects of greenspace on aggressive behaviors, adjusting for within-family/within-individual correlations and other potential confounders.

Results: Both short-term (1- to 6-month) and long-term (1- to 3-year) exposures to greenspace within 1,000 meters surrounding residences were associated with reduced aggressive behaviors. The benefit of increasing vegetation over the range (∼0.12 in NDVI) commonly seen in urban environments was equivalent to approximately 2 to 2.5 years of behavioral maturation. Sociodemographic factors (e.g., age, gender, race/ethnicity, and socioeconomic status) and neighborhood quality did not confound or modify these associations, and the benefits remained after accounting for temperature.

Conclusion: Our novel findings support the benefits of neighborhood greenspace in reducing aggressive behaviors of urban-dwelling adolescents. Community-based interventions are needed to determine the efficacy of greenspace as a preemptive strategy to reduce aggressive behaviors in urban environments.

Keywords: adolescents; aggression; environment; epidemiology; greenspace.

Figure 1

Study flow chart.

Figure 2

Estimated effects on aggressive behaviors associated with short-term (1–6 months) and long-term (1–3 years) Normalized Difference Vegetation Index within residential neighborhood of different buffer sizes (250-, 350-, 500-, 1000-m). Note: All models were conditioned on age, gender, ethnicity, household socioeconomic status, neighborhood quality, and temperature (linear term for short-term; quadratic terms for long-term). Symbols (bars) represent regression coefficients (95% CIs) given by multilevel mixed-effects models adjusting for both within-family and within-individual correlations.