Stability and change in level of probable depression and depressive symptoms in a sample of middle and older-aged adults

Abstract

Findings from studies investigating depression in adults in late life are mixed due to a lack of large longitudinal studies with the power necessary to yield reliable estimates of stability or change. We examined the long-term stability of probable depression and depressive symptomology over a 13-year period in the Dynamic Analyses to Optimize Ageing (DYNOPTA) project. Community-living participants (N = 35,200) were aged 45-103 at baseline, predominantly female (79%), partnered (73%), and educated to secondary school only (61%) and followed for up to 13 years. At baseline, increased age was associated with lower prevalence of probable depression and depressive symptomology. Over time, prevalence of probable depression was stable while levels of depressive symptomology reported a small decline. However, this finding was not consistent for all age groups; there was evidence for increasing levels of depressive symptomology, but not probable depression, as individuals aged. This effect was particularly notable among males aged 70 plus years. These results answer important questions relating to the longitudinal prevalence of probable depression and depressive symptomology in a sample of older Australians. These findings have policy implications for mental health service provision for older adults.