Does the use of SSRIs reduce medical care utilization and expenditures?

BACKGROUND Although selective serotonin reuptake inhibitors (SSRIs) are more expensive than tricyclic antidepressants (TCAs), SSRIs may reduce overall health costs compared with TCAs through improved compliance and reduced need for other medical care services. Economic evaluation studies using clinical trial or claims data have not accurately estimated the actual costs associated with antidepressants because they did not appropriately address two issues: the heterogeneity of SSRI and TCA users and the use of antidepressants for non-indicated symptoms. AIMS OF THE STUDY This study estimates the relative substitution effect of SSRIs on the overall utilization of outpatient and inpatient care and other prescription drugs compared to TCAs. This study identifies and controls for heterogeneities in diagnosis among SSRI and TCA users and looks for variations in substitution effects across utilization. METHODS To estimate the direct effect of SSRIs compared with TCAs on the utilization of other medical care resources in a naturalistic setting, this study uses the Medical Expenditure Panel Survey, national panel survey data, from 1996 to 1998. The main model of analysis is a two-part regression: the first part is a probit model of any use and the second part is a log linear model of expenditures among users. Baseline physical health status, depression severity, and socioeconomic factors that could affect antidepressant choice and medical care utilization are controlled for. RESULTS A considerable fraction of antidepressant use, especially among TCA users, is for reasons other than depression. After controlling for the heterogeneity in SSRI and TCA users, this study does not find consistent evidence of the substitution of SSRIs for other medical care. Although SSRIs, compared with TCAs, reduce overall outpatient visits and other prescription drugs, they increase the utilization of these services for depression. Antidepressant choice does not influence the utilization or expenditure level for inpatient services which composed the largest part of medical expenditure in this study sample. Results are robust when the analysis is restricted to the SSRI or TCA users with a depression diagnosis. DISCUSSION The potential cost-incremental effect of SSRIs over TCAs for the treatment of depression can be compromised by the reduced utilization for symptoms other than depression among SSRI users. This study uses national survey data and takes into account the heterogeneity of SSRI and TCA users so the results can be generalized to real clinical practice. IMPLICATIONS FOR HEALTH CARE PROVISION The costs associated with antidepressants are not only for the treatment of depression symptoms. Antidepressants are commonly prescribed for conditions for which the clinical and economic benefits are not established. This practice may lead to significant unnecessary healthcare expenses. IMPLICATIONS FOR HEALTH POLICIES Antidepressant prescriptions for non-indicated conditions should be considered in setting policies designed to control costs associated with antidepressants and in developing clinical guidelines for antidepressant prescription. IMPLICATIONS FOR FUTURE RESEARCH Future research on the economic evaluation of antidepressants should consider the use of antidepressants for health conditions other than depression. The economic incentives for and clinical benefits of the prescription of antidepressants for non-indicated conditions could be explored in future research.