Objective: A history of depression has been linked to an increased dementia risk. This risk may be particularly high in recurrent depression due to repeated brain insult. We investigated whether there is a dose-dependent relationship between the number of episodes of elevated depressive symptoms (EDS) and the risk for mild cognitive impairment (MCI) and dementia.Methods: A total of 1,239 older adults from the Baltimore Longitudinal Study of Aging were followed for a median of 24.7 years. Diagnoses of MCI and dementia were made based on prospective data. Participants completed the Center for Epidemiologic Studies Depression Scale at 1-to 2-year intervals and were considered to have an EDS if their score was Ն16. Kaplan-Meier survival curves, log-rank test for trend for survivor functions, and Cox proportional hazards models were conducted to examine the risk of MCI and dementia by number of EDS. Results:We observed a monotonic increase in risk for all-cause dementia and Alzheimer disease as a function of the number of EDS. Each episode was associated with a 14% increase in risk for all-cause dementia. Having 1 EDS conferred an 87%-92% increase in dementia risk, while having 2 or more episodes nearly doubled the risk. Recurrence of EDS did not increase the risk of incident MCI. Conclusions:Our findings support the hypothesis that depression is a risk factor for dementia and suggest that recurrent depression is particularly pernicious. Preventing the recurrence of depression in older adults may prevent or delay the onset of dementia. Neurology Late-life depression is associated with cognitive impairment and dementia. Converging evidence suggests that depressive symptoms (DS) and major depression are prevalent in dementia, 1 but whether depression is a prodrome of dementia 2,3 or a risk factor for dementia 4,5 or they simply have similar neuropathologic substrates 6 is a matter of dispute. According to a recent meta-analysis, 7 the preponderance of evidence supports 3 possible hypotheses to explain the association between depression and dementia: 1) depression is a prodrome of dementia, 2) depression affects the threshold for manifesting dementia, or 3) depression leads to hippocampal damage through a glucocorticoid cascade, thus contributing to the development of dementia.The latter hypothesis proposes that glucocorticoid hypersecretion observed in some individuals with major depression increases neuronal death in the hippocampus due to overexpression of glucocorticoid receptors in that region.8 Based on this model, recurrent depressive episodes would be expected to result in greater hippocampal damage due to repeated insults to the brain.Editorial,

The concept of ‘Successful Aging’ has long intrigued the scientific community. Despite this long-standing interest, a consensus definition has proven to be a difficult task, due to the inherent challenge involved in defining such a complex, multi-dimensional phenomenon. The lack of a clear set of defining characteristics for the construct of successful aging has made comparison of findings across studies difficult and has limited advances in aging research. The domain in which consensus on markers of successful aging is furthest developed is the domain of physical functioning. For example, walking speed appears to be an excellent surrogate marker of overall health and predicts the maintenance of physical independence, a cornerstone of successful aging. The purpose of the present article is to provide an overview and discussion of specific health conditions, behavioral factors, and biological mechanisms that mark declining mobility and physical function and promising interventions to counter these effects. With life expectancy continuing to increase in the United States and developed countries throughout the world, there is an increasing public health focus on the maintenance of physical independence among all older adults.

Objectives-The impact of depressive symptoms on cognitive decline in older adults remains unclear due to inconsistent findings in the literature. It is also unclear whether effects of depressive symptoms on cognitive decline vary with age. This study investigated the effect of concurrent, baseline, and average depressive symptoms on cognitive functioning and decline, and examined the interactive effect of age and depressive symptoms on cognition. Design-Prospective observational design with examination of cognitive performance and depressive symptoms at 1-2 year intervals for up to 26 years.