This proposal seeks support to expand the evaluation of an innovative social policy experiment to consider impacts on the physical and mental health of youth. The Moving to Opportunity (MTO) demonstration randomly assigned some public housing families but not others rental housing subsidies to relocate to less disadvantaged neighborhoods. The program thus experimentally generated large differences in neighborhood characteristics for otherwise comparable groups of low-income families. A follow-up study around 5 years after randomization found beneficial effects of MTO moves on mental health and risky behaviors for female youth but not male youth, and had little effect on physical health aside from an increase in injury rates for male youth. However these results are not informative about the long-term effects of neighborhood change on health, and mental health was measured using broad screening measures that made it impossible to evaluate the clinical significance of effects. We seek funding to address these problems by carrying out a follow-up survey of MTO youth roughly 10 years after randomization that assesses effects on physical and mental health to address the following questions: 1. What are the effects on physical health, substance use, and the onset and persistence of DSM-IV mental disorders up through early adulthood of moving to a less disadvantaged neighborhood during childhood? 2. What are the pathways through which these physical and mental health effects occur? 3. How and why do these results depend on gender, age at time of move and pre-move health? 4. How do the effects of neighborhood mobility on health specify the effects of the intervention on other outcomes related to work, family, schooling, criminal involvement, and basic decision-making processes? The overarching goal of the proposed research is to understand the effects and processes by which neighborhoods affect health, and to create a public use dataset that is archived and made available for secondary analysis.