Patient preferences for depression treatment programs and willingness to pay for treatment.

BACKGROUND

Current estimates of the societal costs of depression do not include estimates of how much individuals diagnosed with Major Depressive Disorder (MDD) would be willing to pay to eliminate their depression or how much they would have to be paid in order to accept continued depression. Choice-question data and discrete-choice random-utility models provide a useful method for valuing changes in mental health and mental-health treatment programs.

AIMS OF THE STUDY

(i) To demonstrate how choice questions and discrete-choice random-utility models can be used to estimate preferences over treatment programs for depression and willingness-to-pay (WTP) to eliminate depression. (ii) To investigate whether consumption of goods provides less utility when one is depressed (an anhedonia effect) and, if so, the magnitude of the effect. (iii) To model and estimate the extent of heterogeneity in preferences for treatment programs for depression. (iv) To derive preliminary estimates of WTP and willingness-to-accept (WTA) for eliminating depression, both with, and without side effects.

METHODS

The data are from a choice-question survey of 104 individuals diagnosed with a new episode of MDD. Individuals indicated their preferred treatment from options that varied in effectiveness, hours of psychotherapy per month, use of anti-depressants, money costs, and side effects (weight gain, little or no interest in sex, inability to orgasm). Choices over treatment alternatives, including no treatment, were modeled using a discrete-choice random-utility model. Preference parameters were estimated using maximum likelihood estimation.

RESULTS AND DISCUSSION

Estimated WTP to eliminate MDD is large but side effects can substantially reduce WTP. Preferences over treatment programs, and WTP, vary as a function of the individual's age, gender, income category, body-mass-index, and family composition. Some depressed individuals seeking treatment have a high estimated probability of choosing no treatment. Depression is found to have a direct, negative impact on utility, as expected. It also has an indirect effect: utility from consumption is found to decrease the more severe one's level of depression. The magnitude of this indirect effect is estimated. This indirect effect manifests itself by driving a wedge between estimated WTP to eliminate depression and WTA to accept continued depression. Preferences for treatment are only being estimated for those individuals who are referred to or directly seek treatment at a mental-health clinic, not for the general population of depressed. The estimates are plausible but the sample size is small, so caution is warranted.

IMPLICATIONS

The WTP estimates suggest that depression imposes a high cost on society beyond the cost of treatment and the cost of lost output. WTP should be included in any benefit-cost analysis of whether additional societal resources should be allocated to the treatment of depression. Side effects from anti-depressants also impose a large cost on society. Estimates such as the ones reported here could provide a mechanism for better matching treatment programs to the patient and thus potentially reduce non-adherence. The WTP estimates suggest that the pharmaceutical industry could increase revenues by making anti-depressants more effective or reducing their side effects.