How Do Different Age Groups Use Benzodiazepines and Antidepressants? Analysis of an Australian Administrative Database, 2003-6

Background: The use of antidepressants and benzodiazepines is increasing in Australia and worldwide, and it is thought that some of the prescribing of these classes of drugs may be inappropriate. However, the demographic characteristics of the subgroups of the population responsible for this increase remain unexplored. Objective: The aim of this study was to examine changes in the utilization of antidepressants and benzodiazepines between different age groups within Australia from 2003 to 2006. Methods: The Australian Pharmaceutical Benefits Scheme administrative database was used to obtain dispensing data for all antidepressants and publicly subsidized benzodiazepines. Changes in utilization (amounts and patterns of use of different compounds) were compared between different age groups from 2003 to 2006. The WHO Anatomic Therapeutic Chemical/Defined Daily Dose system was used. Results: Use of antidepressants increased from 2003 to 2006, and in each year increased with age, with those >= 65 years having the greatest use. Differences were seen in the antidepressant most utilized, with the elderly using more tricyclic antidepressants than those who are younger. The utilization of benzodiazepines decreased from 2003 to 2006 in elderly individuals and those receiving social welfare benefits. Individuals aged >= 85 years had the highest use of benzodiazepines and used more long-acting benzodiazepines compared with those aged 35-44 years. Conclusion: The elderly still account for most use per capita of benzodiazepines. Some of this use may be inappropriate (e.g. use of long-acting benzodiazepines) and, hence, may represent a useful target for future educational intervention. The elderly also still account for the largest per capita use of antidepressants.