a1 Discipline of Public Health, University of Adelaide, Adelaide, Australia
a2 Sansom Institute, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia, Australia
a3 School of Nursing and Midwifery, University of South Australia, Adelaide, South Australia, Australia
a4 School of Psychology and Flinders Centre for Ageing Studies, Flinders University, South Australia, Australia
Background: Depression is one of the leading contributors to the burden of non-fatal diseases in Australia. Although there is an overall increasing trend in antidepressant use, the relationship between use of antidepressants and depressive symptomatology is not clear, particularly in the older population.
Methods: Data for this study were obtained from the Australian Longitudinal Study of Ageing (ALSA), a cohort of 2087 people aged over 65 years at baseline. Four waves of home interviews were conducted between 1992 and 2004 to collect information on sociodemographic and health status. Depressive symptoms were measured by the Center for Epidemiologic Studies – Depression Scale. Use of antidepressants was based on self-report, with the interviewer able to check packaging details if available. Longitudinal analysis was performed using logistic generalized estimating equations to detect if there was any trend in the use of antidepressants, adjusting for potential confounding factors.
Results: The prevalence of depressive symptoms was 15.2% in 1992 and 15.8% in 2004 (p > 0.05). The prevalence of antidepressant users increased from 6.5% to 10.9% (p < 0.01) over this period. Among people with depressive symptoms, less than 20% were taking antidepressants at any wave. Among people without depressive symptoms, the prevalence of antidepressant use was 5.2% in 1992 and 12.0% in 2004 (p < 0.01). Being female (OR = 1.67, 95%CI: 1.25–2.24), having poor self-perceived health status (OR = 1.17, 95%CI: 1.04–1.32), having physical impairment (OR = 1.48, 95%CI: 1.14–1.91) and having depressive symptoms (OR = 1.62, 95%CI: 1.24–2.13) significantly increased the use of antidepressants, while living in community (OR = 0.51, 95%CI: 0.37–0.71) reduced the risk of antidepressant use.
Conclusions: Use of antidepressants increased, while depressive symptoms remained stable, in the ALSA over a 12-year period. Use of antidepressants was low for people with depressive symptoms.
(Received August 17 2009)
(Revised September 28 2009)
(Revised November 12 2009)
(Accepted November 13 2009)
(Online publication January 28 2010)
c1 Correspondence should be addressed to: Dr. Ying Zhang, Quality Use of Medicines and Pharmacy Research Centre, Reid Building, Frome Road, Adelaide, South Australia 5005, Australia. Phone: +61 8 83022763; Fax: +61 8 8302 1087. Email: firstname.lastname@example.org.