Young Children's Mental Health Improves Following Medicaid Expansion to Low-Income Adults.

Objective: We investigate whether the Affordable Care Act's Medicaid expansion, implemented in 2014, improved the mental health of young children whose parents are in the policy's target population. We study children ages 2 to 3 in families with incomes less than 138% of the federal poverty level.

Methods: We use restricted National Health Interview Survey data covering the United States from 2010 to 2018 to conduct an event study-a flexible version of difference-in-differences-of the Medicaid expansion's effects on Mental Health Indicator values for young children. We estimate effects using ordered logit regression.

Results: Children's mental health was statistically significantly better in Medicaid expansion states, compared with non-expansion states, in 3 of 4 post-expansion years. There were no differences between expansion and non-expansion states in the pre-expansion period, lending support to the causal interpretation that the expansion improved children's mental health.

Conclusions: While Medicaid expansion targets low-income adults, our evidence indicates it improves low-income children's mental health. The expansion is a two-generation investment in prevention. It helps lay a foundation for strong mental health in children's early years and beyond.