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Online ISSN: 1099-176X    Print ISSN: 1091-4358
The Journal of Mental Health Policy and Economics
Volume 10, Issue 3, 2007. Pages: 133-144
Published Online: 8 Sep 2007

Copyright © 2007 ICMPE.


 

How Does the Persistence of Depression Influence the Continuity and Type of Health Insurance and Coverage Limits on Mental Health Therapy?

Anthony Masaquel,1 Kenneth Wells,2 Susan L. Ettner*3

1 Ph.D., M.P.H., Department of Health Services, UCLA School of Public Health, Los Angeles, CA, USA
2 M.D., Department of Psychiatry & Behavioral Sciences, UCLA School of Medicine, Los Angeles, CA, USA
3 Ph.D., Division of General Internal Medicine & Health Services Research, UCLA School of Medicine, Los Angeles, CA, USA

* Correspondence to: Susan L. Ettner, Ph.D., Address: Division of General Internal Medicine & Health Services Research, UCLASchool of Medicine, 911 Broxton Plaza, Box 951736, Los Angeles, CA90095, USA.
Tel.: 310-794 2289
Fax: 310-794 0732
E-mail: settner@mednet.ucla.edu

Source of Funding: This study was supported by the Robert Wood Johnson Foundation-funded Economic Research Initiative on the Uninsured (PI Ettner) and the Center for Research on Quality in Managed Care (National Institute of Mental Health grant #P30 MH068639, PI Wells). The data used for the study were collected as part of the Partners in Care study (National Institute of Mental Health grant #R01MH061570, PI Wells).

Abstract

Data from a randomized controlled trial of a depression intervention were used to estimate the structural effect of the persistence of depression on continuity and type of health insurance and coverage limits on mental health therapy. Approximately 945 adult patients from managed care settings and who were primarily depressed and insured at baseline were examined over an 18-month period.  Based on probit models (single-equation for public and private insurance, and instrumental variables for generosity of mental health coverage, for which depression was endogenous), depression burden days increased the probability of having any public health insurance coverage and decreased the probability of generous mental health coverage.  However, these effects were small in magnitude.  Reverse causality may be more of a concern when examining the influence of depression on mental health care coverage than on health insurance in general.  

 

Aim of the Study: To determine the structural effect of the persistence of depression on continuity and type of health insurance and coverage limits on mental health therapy.

Methods: Data came from the Partners in Care study (PIC), a randomized controlled trial examining the effect of quality improvement (QI) programs involving medication or psychotherapy on the outcomes of initially depressed patients in seven managed care settings. The sample included approximately 945 adult patients under the age of 63 years who were primarily depressed and insured at baseline. Single-equation multivariate probit regressions were estimated to determine the association of depression burden days aggregated over the 6 to 24-month period post-baseline with the following dichotomous outcomes: continuous health insurance over 6 to 24 months; continuous private health insurance over 6 to 24 months; any public health insurance over 6 to 24 months; and reporting no insurance limits on mental health therapy coverage at 24 months. Other control variables included baseline insurance status, age, sex, race, marital status, education, income, assets, fixed site effects, and (in sensitivity analyses) number of medical comorbidities, alcohol use and drug use. To address the possibility of endogeneity bias in the relationship between depression and insurance, consistent estimates were derived from instrumental variables (IV) probit regressions and the endogeneity of depression burden days was tested. Potential instruments included the random assignment to intervention and control groups in the PIC study, type of depression at baseline, and baseline Mental Component Summary (MCS) score from the Short Form-12 (SF-12). In sensitivity analyses, data pooled (rather than aggregated) across waves were used to estimate probit and IV probit regressions, using Generalized Estimating Equations methods to adjust for within-person correlation of the error terms.

Results: Evidence was found that depression burden days were exogenous to all of the health insurance outcomes except for coverage limits on mental health therapy. Based on the appropriate estimates (single-equation if exogenous, IV if endogenous), depression burden days appeared to increase the probability of having any public health insurance coverage and decrease the probability of having no coverage limits on mental health therapy. However, these effects were small in magnitude.

Conclusions:  Reverse causality may be more of a concern when examining the influence of depression on mental health care coverage than on health insurance in general. Consistent with the government's historical role in financing mental health services, patients whose depression persisted to a greater extent were slightly more likely to have some public health insurance during an 18-month follow-up period. Furthermore, they were slightly more likely to have limits on mental health therapy coverage, suggesting that insurers may be more likely to control access at the level of the benefits structure than at the level of insurance coverage per se. Future analyses should examine the mediating factors in the relationship between depression and limits on mental health therapy coverage, e.g., diminished employment opportunities with large companies that offer more generous benefits.


Received 14 November 2006; accepted 24 July 2007

Copyright 2007 ICMPE