National Trends in the Use of Antidepressants Between 1997 and 2009 and the Role of Medicare Part D Implementation

This study examined national trends in antidepressant use before and after implementation of Medicare Part D and compared utilization among individuals with different types of insurance.

The data source was the Medical Expenditure Panel Survey Household Component (1997–2009), and logistic regression was used for the analysis.

The odds of antidepressant use among people with depression increased between 1997 and 2009 in each insurance group (Medicare: adjusted odds ratio [AOR]=3.30, 95% confidence interval [CI]=1.84–5.92; Medicaid: AOR=2.97, CI=2.01–4.40; dually eligible for Medicare and Medicaid: AOR=2.24, CI=1.11–4.54; and private coverage: AOR=6.63, CI=5.23–8.42). The odds of antidepressant use after implementation of Part D increased more among Medicare beneficiaries than among Medicaid beneficiaries (AOR=1.35, CI=1.05–1.72).

The use of antidepressants among people with depression increased in all insurance groups up to 2009; however, the patterns of utilization and the degree of increase over time differed by insurance type.