Using willingness to pay to measure family members' preferences in mental health.

Background: Willingness to pay is a valuation technique that has rarely been applied in mental health economics. First used in environmental economics to measure the intangible value of environmental improvements, WTP has increasingly been used in health care economics. The technique may be useful in mental health policy research where it can be critical to include the intangible impact of mental health treatment on individuals other than the person with illness, such as family members, in cost-benefit analyses. Aims of the Study: The goal of the study was to test the application of WTP in a sample of individuals who have family members with serious mental illness. This paper describes the survey development process and the feasibility analysis that was conducted as part of the study. Methods: A mail survey was designed by the author in two phases and utilized cognitive pretests and focus group pretests in the process of development. Qualitative analysis of this process resulted in a revised survey instrument that was then distributed to a random sample of 2000 individuals who have family members with mental illness. Feasibility was evaluated based upon the study response rate, the willingness to pay item response rate and an outlier response analysis. Results: Qualitative analysis during the survey development process found that it was critical to consider two areas of concern in the application of WTP with this population in the mental health field. Some respondents experienced a highly emotional response to the initial versions of the survey, and complex probabilities were difficult for the respondents to answer. These findings resulted in significant modifications in the survey design. The analysis of response rate, WTP item non-response rate, and outlier responses found no significant concerns regarding overall feasibility of WTP with this population. Discussion: Based upon the results from this study, WTP is a potentially useful tool for further research in the mental health policy and economics field. However, significant accommodations must be made in survey design to account for a possibility of a high level of emotional distress for those dealing with the illness of a family member. Some of these modifications may be in contrast to the recommendations currently being followed in health care economics. Face-to-face surveys may be preferred in some cases, such as with elderly respondents. Limitations of this study include the lack of targeted follow-up due to the anonymous study design and the fact that there are so few models for WTP studies in mental health. Implications for Mental Health Policy: Given that effective mental health programs can be matched with additional expenditures, it is important to explore comprehensive measures of value for treatment in cost-benefit analysis. The values of persons whose family members have serious mental illness are important to consider in setting policy. The success of this study suggests that WTP could be used in other settings, e.g., to understand community preferences for mental health treatment programs, to understand differences in preferences across multiple stakeholder groups.