Objective: To estimate the prevalence of depression among older adults in Australia.
Method: All general practitioners in Australia's five most populous states who satisfied certain eligibility criteria (e.g., sufficient weekly working hours, sufficient numbers of elderly patients) were invited to participate. Those who consented were asked to identify all of their patients aged 60+ and invite them (either directly or via the study team) to complete a questionnaire. The questionnaire identified those who had experienced 'clinically significant depression' and those who had experienced a 'major depressive episode' in the past two weeks, via the Patient Health Questionnaire (PHQ-9). Consenting patients completed the questionnaire and returned it to the study team in a reply-paid envelope.
Results: In total, 22,251 patients returned questionnaires. Overall, the age-adjusted rate of clinically significant depression was 8.2% (95%CI=7.8%-8.6%), with the age-adjusted rates for males being 8.6% (95%CI=7.9%-9.2%) and for females being 7.9% (95%CI=7.4%-8.4%). The overall, male and female age-adjusted rates for a major depressive episode were 1.8% (95%CI=1.6%-2.0%), 1.9% (95%CI=1.6%-2.2%) and 1.7% (95%CI=1.5%-2.0%), respectively.
Discussion: Our study suggests that depression among older people is a major public health problem. The above estimates provide guidance for efficient planning of services, and establish a baseline against which preventive and treatment interventions can be assessed. Armed with this information, we can progress efforts at reducing this major health problem and its consequences.