Cost-effectiveness of antidepressant medications

BACKGROUND: Antidepressant medications have been shown to effectively relieve symptoms, improve interpersonal and occupational functioning and reduce disability from coexisting medical conditions. Although the newer selective serotonin reuptake inhibitors (SSRIs) have improved tolerability, are easier to take and are associated with longer lengths of therapy when compared with the tricyclic antidepressants (TCAs), the relative cost-effectiveness of alternative antidepressants remains unclear. AIMS OF THE STUDY: This study seeks to determine (i) the probability that relapse or recurrence of depression can be prevented by appropriate antidepressant choice, (ii) the cost associated with relapse or recurrence of depression and (iii) the relative cost-effectiveness of alternative antidepressants. METHODS: We use a quasi-experimental design to compare claims from a state Medicaid plan for TCA and SSRIs users. RESULTS: Premature discontinuation of antidepressant medication is the strongest predictor of relapse and recurrence. Antidepressant choice was not an independent predictor of relapse or recurrence. The effect of relapse and recurrence on expenditures is complex, with a non-significant trend toward lower expenditures for those who had longer periods between episodes of depression two years after initiation of treatment for the first episode. We were unable to replicate prior research results regarding the impact of SSRIs on duration of therapy in this Medicaid plan. CONCLUSIONS: Premature discontinuation of antidepressant treatment is associated with a high probability of relapse and recurrence. Health care expenditures are not altered by preventing relapse and recurrence. We suggest that antidepressant medications associated with reduced probability of premature discontinuation should be considered cost-effective. IMPLICATIONS FOR HEALTH CARE PROVISION AND USE: There are very few variables which health care providers can use to improve the outcomes and associated economic consequences of depression. Among these factors, treatment choice and adherence to the prescribed treatment are likely candidates. In this paper, we suggest that adherence to antidepressant medication results in substantial improvement in the time to relapse or recurrence of depression. Choice of an SSRI may thus improve treatment outcome by lengthening remission. In addition, this choice is not associated with higher costs. IMPLICATIONS FOR HEALTH POLICY FORMULATION: Depressive illnesses are associated with high rates of health service use and functional impairment. Thus, the societal burden is quite high. This paper furthers the debate regarding the relative cost-effectiveness of antidepressant medications, and our findings suggest several ways that policy makers can improve the care of depressed individuals at little additional cost. Specifically our findings highlight the importance of adherence to current recommendations regarding the length of antidepressant treatment and suggest several methods for improving this important outcome. IMPLICATIONS FOR FURTHER RESEARCH: The relative cost-effectiveness of alternative antidepressant medications continues to be an important and unsolved issue. We suggest the need for future research in this area using a variety of research designs appropriate to the question. The quasi-experimental approach outlined here seems promising in this regard.