A systematic review and meta-analysis of the impact of environmental disadvantage on youth delayed reward discounting.

Delayed reward discounting (DRD), the tendency to prefer smaller rewards available immediately relative to larger rewards available after a delay, is associated with numerous health outcomes across the lifespan. Emerging literature points to the central role of early environments, specifically factors reflecting harshness (including lack of resources) and unpredictability (exposure to instability and stressful events) in the development of DRD. Yet, existing research uses disparate indicators of environmental risk and often draws on small samples resulting in conflicting findings, making comparisons across studies challenging. The current systematic review examined environmental factors that may place youth at greatest risk for heightened DRD and subsequent negative health outcomes. Search results identified 28 articles reflecting 20 unique samples. Additionally, meta-analyses were conducted to examine overall effects for the two most commonly examined environmental predictors (family income and family history of substance use disorder). Results suggest small-to-medium associations of environmental risk with DRD, with smaller associations observed for more distal predictors of harshness (e.g., family income) and larger associations among more proximal indicators of environmental instability (e.g., harsh parenting and parental pathology). Findings highlight the role of environmental factors on DRD development and may inform future interventions.