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Association of Federal Mental Health Parity Legislation With Health Care Use and Spending Among High Utilizers of Services

Haffajee, Rebecca L., JD, PhD, MPH*; Mello, Michelle M., JD, PhD, M.Phil; Zhang, Fang, PhD; Busch, Alisa B., MD, MS§,∥,¶; Zaslavsky, Alan M., PhD; Wharam, J. Frank, MB, BCh, BAO, MPH

doi: 10.1097/MLR.0000000000001076
Original Articles

Background: Decades-long efforts to require parity between behavioral and physical health insurance coverage culminated in the comprehensive federal Mental Health Parity and Addiction Equity Act.

Objectives: To determine the association between federal parity and changes in mental health care utilization and spending, particularly among high utilizers.

Research Design: Difference-in-differences analyses compared changes before and after exposure to federal parity versus a comparison group.

Subjects: Commercially insured enrollees aged 18–64 with a mental health disorder drawn from 24 states where self-insured employers were newly subject to federal parity in 2010 (exposure group), but small employers were exempt before-and-after parity (comparison group). A total of 11,226 exposure group members were propensity score matched (1:1) to comparison group members, all of whom were continuously enrolled from 1 year prepolicy to 1–2 years postpolicy.

Measures: Mental health outpatient visits, out-of-pocket spending for these visits, emergency department visits, and hospitalizations.

Results: Relative to comparison group members, mean out-of-pocket spending per outpatient mental health visit declined among exposure enrollees by $0.74 (1.40, 0.07) and $2.03 (3.17, 0.89) in years 1 and 2 after the policy, respectively. Corresponding annual mental health visits increased by 0.31 (0.12, 0.51) and 0.59 (0.37, 0.81) per enrollee. Difference-in-difference changes were larger for the highest baseline quartile mental health care utilizers [year 2: 0.76 visits per enrollee (0.14, 1.38); relative increase 10.07%] and spenders [year 2: $−2.28 (−3.76, −0.79); relative reduction 5.91%]. There were no significant difference-in-differences changes in emergency department visits or hospitalizations.

Conclusions: In 24 states, commercially insured high utilizers of mental health services experienced modest increases in outpatient mental health visits 2 years postparity.

*Department of Health Management and Policy, University of Michigan School of Public Health, Ann Arbor, MI

Stanford Law School and Department of Health Research and Policy, Stanford University School of Medicine, Stanford, CA

Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston

§McLean Hospital, Belmont

Departments of Psychiatry

Health Care Policy, Harvard Medical School, Boston, MA

Earlier versions of this manuscript were presented at the 2014 Robert Wood Johnson Foundation Public Health Law Research Program Annual Meeting in Atlanta, GA (podium presentation), at a 2014 Pharmaceutical Policy Research Seminar held by Harvard Medical School/Harvard Pilgrim Health Care Institute in Boston, MA, and at the 2015 AcademyHealth Annual Research Meeting, Minneapolis, MN (poster presentation and winner of the best student poster award).

This study obtained ethics approval from institutional review boards at Harvard Pilgrim Health Care Institute (#386759) and University of Michigan (#HUM00121126). Participant consent was waived for this study of secondary data.

The content of this article is solely the responsibility of the authors and does not necessarily represent the official views of University of Michigan School of Public Health, Harvard Medical School, Harvard Pilgrim Health Care Institute, Stanford Law School, Stanford University School of Medicine, or McLean Hospital.

R.L.H.: received dissertation stipend support from Pharmaceutical Policy Research and Thomas O. Pyle Fellowships from Harvard Medical School and Harvard Pilgrim Health Care Institute, a Public Health Law Research Program Strategic and Targeted Research Program Dissertation Grant Award from the Robert Wood Johnson Foundation, and a Health Policy Training Grant from the National Institute of Mental Health. R.L.H.: maintained independence from her financial supporters, who had no role in the design and conduct of the study; collection, management, analysis, or interpretation of the data; preparation, review, or approval of the manuscript; or decision to submit the manuscript for publication. The remaining authors declare no conflict of interest.

Reprints: Rebecca L. Haffajee, JD, PhD, MPH, Department of Health Management and Policy, University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109. E-mail:

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