The course of depression in the elderly: a longitudinal community-based study in Australia
Background. We report the outcome of depressive states after 3-4 years in a community sample of the elderly.
Methods. A sample of 1045 persons aged 70+ years in 1990–1 was re-interviewed after 3·6 years.
Results. Mortality (21·7%) and refusal or non-availability (10·4%) were higher in those who initially had had a diagnosis or symptoms of depression. Of those with an ICD-10 depressive episode in 1990–1, 13% retained that diagnosis. Of those who were not depressed initially only 2·5% had become cases. Depression was unrelated to age or apolipoprotein E genotype. The best predictors of the number of depressive symptoms at follow-up was the number at Wave 1, followed by deterioration in health and in activities of daily living, high neuroticism, poor current health, poor social support, low current activity levels and high service use. Depressive symptoms at Wave 1 did not predict subsequent cognitive decline or dementia.
Conclusions. Non-random sample attrition is unavoidable. ICD-10 criteria yield more cases than other systems, while continuous measures of symptoms confer analytical advantages. Risk factors for depressive states in the elderly have been further identified. The prognosis for these states is favourable. At the community level, depressive symptoms do not seem to predict cognitive decline, as they do in referred series.
Address for correspondence: Professor A. S. Henderson, NHMRC Social Psychiatry Research Unit, The Australian National University, Canberra, ACT 0200, Australia.