The broad goals of this study are to strengthen our understanding of how social determinants of health, specifically socioeconomic conditions and associated stressors, can be mitigated to improve child mental health within the context of a preventive intervention. Socioeconomic conditions and associated stressors have significant impact on mental health across the lifespan (Healthy People 2020, U.S. Department of Health and Human Services, 2019). Recent estimates from the National Center on Poverty suggest that 40% of children in the US live below 200% of the poverty line, with 21% of children living in poverty. Children from disadvantaged backgrounds are 2-3 times as likely to exhibit mental health problems compared to more advantaged peers. One key theoretical perspective addressing the link between socioeconomic stress and child outcomes is the Family Stress Model (FSM), which suggests that socioeconomic stress negatively affects parental well-being and parenting, leading to risk for poorer child mental health. ParentCorps is a universal family-centered preventive intervention delivered as an enhancement to Pre-K programs for children attending high-poverty schools. Intervention includes professional development for teachers and a program offered to all Pre-K families. Two cluster RCTs of ParentCorps found impacts on parenting and child self-regulation, with sustained effects on child mental health (both emotional and behavior problems) in second grade. While ParentCorps has demonstrated the potential to bolster parent and child well-being in the context of concentrated disadvantage, the extent to which it may mitigate risk stemming from macroeconomic stress remains unclear. Macroeconomic stress stemming from the Great Recession (GR) has been shown to increase risk for child mental health problems, with evidence of indirect effects through less optimal parenting and parent well-being. Given that ParentCorps supports parenting and child mental health, it may also protect against the added strain of macroeconomic stress. This project seeks to capitalize on the timing of an RCT of ParentCorps which involved assessments with 1,050 families (4 cohorts of Pre-K children) that occurred from 2005 to 2012 (before, during, and after the GR). By linking existing RCT data with time-matched macroeconomic data, this project utilizes a “natural experiment” within an RCT to address two specific aims: (1) to evaluate the extent to which ParentCorps mitigates risk for child mental health problems associated with macroeconomic stress, and (2) to explore mechanisms through which such mitigation may occur by examining links between macroeconomic stress and parent well-being and parenting, in line with the FSM. Analyses explore moderation of links between macroeconomic stress and outcomes by intervention status through mixed-effects models, as randomization was at the school-level. The project fits NIMH’s Strategic Objective 3 “to interrogate putative intervention...