Medical morbidity and severity of depression in a large primary care sample of older Australians: the DEPS-GP project

Abstract

Objectives: To estimate the prevalence of depression among older Australians with common medical morbidities, and to determine the association between poor physical health and depression in this age group. Design: Cross-sectional, postal questionnaire survey. Setting and participants: 20 183 community-dwelling adults aged 60 years and over, under the care of 383 general practitioners participating in the Depression and Early Prevention of Suicide in General Practice (DEPS-GP) project (conducted between 2005 and 2008; the data in this article were collected during the baseline phase of the study in 2005). Main outcome measures: Depressive symptoms (measured by the nine-item depression scale of the Patient Health Questionnaire), health status (measured by the 12-item Short Form Health Survey and a medical morbidity inventory), social support (measured by the subjective support subscale from the Duke Social Support Index), and demographic and lifestyle information. Results: 18 190 participants (90.1%) reported having at least one chronic physical health condition, while 1493 (7.1%) experienced clinically significant depression (3.1% major depressive syndrome; 4.0% other depressive syndrome). Most chronic physical illnesses were associated with increased odds of depression, and participants with numerous medical morbidities and a high level of functional impairment were three to four times more likely to have a depressive illness. Conclusions: Depression is more the exception than the rule in later life, and among those who are medically unwell, the level of associated impairment may determine their risk of depression more than their acquired physical illness. Many of the factors associated with depression in medically ill patients are amenable to treatment, and GPs are in a unique position to address this important public health issue.