Original Article

The Effects of State Parity Laws on the Use of Mental Health Care

Harris, Katherine M. PhD*; Carpenter, Christopher PhD†; Bao, Yuhua PhD‡

Author Information

From the *Substance Abuse and Mental Health Services Administration, Rockville, Maryland; †The Paul Merage School of Business, University of California–Irvine, Irvine, California; and the ‡Division of General Internal Medicine and Health Services Research, University of California–Los Angeles School of Medicine, Los Angeles, California.

Dr. Harris is currently affiliated with The Rand Corporation.

This work was supported by SAMHSA's Office of Applied Studies.

This article does not represent the policies or the positions of the Office of Applied Studies, the Substance Abuse and Mental Health Services Administration. No official endorsement by this organization is intended or should be inferred.

Reprints: Katherine Harris, PhD, The Rand Corporation, 1200 South Hayes Street, Arlington, VA 22202. Email: [email protected].

Medical Care 44(6):p 499-505, June 2006. | DOI: 10.1097/01.mlr.0000215813.16211.00

Abstract

Objective: 

We used a quasiexperimental research design to measure the effect of state parity laws on the use of mental health care in the past year.

Methods: 

We pooled cross-sectional data from the 2001, 2002, and 2003 National Surveys on Drug Use and Health. Our sample included 83,531 adults 18 years of age or over with private health insurance stratified by the level of mental and emotional distress experienced in the worst month of the past year. We used a state and year-fixed effects approach to measure the effect of parity. Similar to a difference-in-difference analysis, the effect of parity was measured by comparing pre-/postchanges in mental health service use within states that switched active parity status to changes in service use within states that did not change parity status in the same calendar year. For each subgroup, we report predictions of the percentage point change in any mental health care use, prescription drug use, and outpatient care use resulting from parity laws.

Results: 

Depending on the time window used to define active parity status, we found that parity increased the probability of using any mental health care in the past year by as much as 1.2 percentage points (P < 0.01) for the lower distress group and by as much as 1.8 percentage points (P < 0.05) in the middle distress group. We found no statistically significant changes in service use for the upper distress group. Whether measured differences were attributable to changes in the use of prescription drug or outpatient care also depended on the definition of active parity status.

Conclusions: 

Overall, the results of this study suggest that state parity laws succeeded in expanding access to mental health care for those with relatively mild mental health problems.

© 2006 Lippincott Williams & Wilkins, Inc.

Full Text Access for Subscribers:

Not a Subscriber?

Buy
Request Permissions

You can read the full text of this article if you:

Access through Ovid