The Prescription Pattern and Analyses of Antidepressants under the National Health Insurance Policy in Taiwan

Background: In this study, we examined trends associated with various antidepressants competing in the Taiwanese market, based on data from the National Health Insurance (NHI) Research Database. Methods: The cases of patients diagnosed with depression were selected as the subjects of this study. The prescription and use of antidepressants were analyzed to shed light on the competition in the market and substitution of these drugs, as influenced by the NHI insurance system. Results: The data indicated that the number of patients diagnosed with clinical depression was increased twofold and that the associated expenditure on antidepressants was increased threefold between 1997 and 2004. We also observed the total incremental use of antidepressants in each category, indicating that third-generation antidepressants continued to dominate market, and gradually replaced those of the first-generation antidepressants. The use of second-generation antidepressants was found to have remained relatively unchanged. Among all levels of hospital organizations, third-generation antidepressants were found to be preferred. The medical staff at district hospitals and primary care clinics prescribed more first-generation antidepressants than those at regional hospitals or medical centers. Conclusions: The use of third-generation antidepressants has surpassed that of first-and second-generation. The non-free market drug reimbursement mechanism governed by NHI had influence on prescription patterns of antidepressants in hospitals. All aspects of competition among antidepressants are in line with the Porter's theory of competition.