Purpose: The Moving to Opportunity (MTO) study is typically interpreted as a trial of changes in neighborhood poverty. However, the program may have also increased exposure to housing discrimination. Few prior studies have tested whether interpersonal and institutional forms of discrimination may have offsetting effects on mental health, particularly using intervention designs.
Methods: We evaluated the effects of MTO, which randomized public housing residents in 5 cities to rental vouchers, or to in-place controls (N = 4248, 1997-2002), which generated variation on neighborhood poverty (% of residents in poverty) and encounters with housing discrimination. Using instrumental variable analysis (IV), we derived two-stage least squares IV estimates of effects of neighborhood poverty and housing discrimination on adult psychological distress and major depressive disorder (MDD).
Results: Randomization to voucher group vs. control simultaneously decreased neighborhood % poverty and increased exposure to housing discrimination. Higher neighborhood % poverty was associated with increased psychological distress [BIV = 0.36, 95% confidence interval (CI) 0.03, 0.69] and MDD (BIV = 0.12, 95% CI - 0.005, 0.25). Effects of housing discrimination on mental health were harmful, but imprecise (distress BIV = 1.58, 95% CI - 0.83, 3.99; MDD BIV = 0.57, 95% CI - 0.43, 1.56). Because neighborhood poverty and housing discrimination had offsetting effects, omitting either mechanism from the IV model substantially biased the estimated effect of the other towards the null.
Conclusions: Neighborhood poverty mediated MTO treatment on adult mental health, suggesting that greater neighborhood poverty contributes to mental health problems. Yet housing discrimination-mental health findings were inconclusive. Effects of neighborhood poverty on health may be underestimated when failing to account for discrimination.
Keywords: Discrimination; Housing; Neighborhood poverty; Psychological distress; Randomized controlled trial.