Objective: To determine the costs associated with antidepressant (AD) use by depression and anxiety status in a public-managed health care system.
Methods: Data were obtained from a population-based health survey of 1869 older adults. Depression and anxiety were based on the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, criteria and measured at 2 time points 1 year apart. AD and health service use and costs were identified from provincial administrative databases and included hospitalizations, physician fees, outpatient medications, and ambulatory visits. Patient costs considered were related to drug copayments, transportation, and time spent seeking medical care. Annual costs associated with AD use were studied as a function of mental health status at baseline and follow-up interviews (persistence, incidence, remission, or no illness). Generalized linear models with a gamma distribution were used to control for individual factors.
Results: The costs incurred by participants using ADs as a whole (17.8%) reached $6678 (95% CI $5449 to $8182), significantly more than in participants not using ADs ($4698; 95% CI $3710 to $5949). AD use was associated with greater total adjusted costs among respondents with no depression (adjusted difference = $1769; 95% CI $236 to $3702) and no anxiety (adjusted difference = $1845; 95% CI $203 to $3486).
Conclusion: The results showed that AD use was not associated with cost savings in any group, and indeed with greater costs among participants who were neither depressed nor anxious at any time point. Future cost studies may consider the analyses of different AD classes regarding the different clinical mental health profiles in older adults.