The Effects of the Affordable Care Act Adult Dependent Coverage Expansion on Mental Health.

BACKGROUND: In September 2010, the Affordable Care Act increased the availability of private health insurance for young adult dependents in the United States and prohibited coverage exclusions for their pre-existing conditions. The coverage expansion improved young adults' financial protection from medical expenses and increased their mental health care use. These short-term effects signal the possibility of accompanying changes in mental health through one or more mechanisms: treatment-induced symptom relief or improved function; improved well-being and/or reduced anxiety as financial security increases; or declines in self-reported mental health if treatment results in the discovery of illnesses.

AIMS: In this study, we estimate the effects of this insurance coverage expansion on young adults' mental health outcomes one year after its implementation.

METHODS: We use a difference-in-differences (DD) framework to estimate the effects of the ACA young adult dependent coverage on mental health outcomes for adults ages 23-25 relative to adults ages 27-29 from 2007-2011. Outcome measures include a global measure of self-rated mental health, the SF-12 mental component summary (MCS), the PHQ-2 screen for depression, and the Kessler index for non-specific psychological distress.

RESULTS: The overall pattern of findings suggests that both age groups experienced modest improvements in a range of outcomes that captured both positive and negative mental health following the 2010 implementation of the coverage expansion. The notable exception to this pattern is a 1.4 point relative increase in the SF-12 MCS score among young adults alone, a measure that captures emotional well-being, mental health symptoms (positive and negative), and social role functioning.

DISCUSSION: This study provides the first estimates of a broad range of mental health outcomes that may be responsive to changes in mental health care use and/or the increased financial security that insurance confers. For the population as a whole, there were few short-term changes in young adults' mental health outcome relative to older adults. However, the relative increase in the SF-12 score among young adults, while small, is likely meaningful at a population level given the observed effect sizes for this measure obtained in clinical trials.

IMPLICATIONS: The vast majority of mental illnesses emerge before individuals reach age 24. Public policy designed to expand health insurance coverage to this population has the potential to influence mental health in a relatively short time frame.