Objectives: The aim of this study was to investigate the prevalence of depression among very old individuals with dementia compared to those without dementia and to examine if there were any differences regarding associated factors between people with or without depression in these conditions.
Methods: In a population-based study in Sweden, 363 participants aged 85 years and above, were evaluated for depression and dementia.
Results: The prevalence of depression was significantly higher among the people with dementia than without dementia, 43% vs. 24% (p < 0.001). Approximately 2/3 of the depressed in both groups used antidepressants and of those, approximately 50% had responded. Depression in the group without dementia was, among other factors, associated with higher total number of medication, the use of significant more analgesics and benzodiazepines, loneliness, inability of going outside and recent loss of child. The loss of a child was the only factor that was independently associated with depression in those with dementia.
Conclusions: The present study confirms that in the very old, depression is more common among people with dementia than without dementia. A large proportion, both with and without dementia, are under-diagnosed and untreated, and in addition many subjects in both groups studied were non-responders to treatment. Many of the factors associated with depression among people without dementia in this study were not associated with depression among those with dementia, thus supporting the theory that the spectrum of associated factors for depression in dementia seems to be different from that for depression in people without dementia.