ABSTRACT. Background and aims:
INTRODUCTIONProspective studies concerning the question whether late life depression is associated with subsequent cognitive decline have yielded conflicting results (1-8). However, there is sufficient evidence to assume that depression is a risk factor for cognitive decline (7). So far, the explanation for the background of this association has remained unclear.The pathological effect of depression on cognitive function may be caused by high levels of glucocorticoids (cortisol). Secretion of glucocorticoids plays a central role in the short-term biological adaptation to stress. However, prolonged stress and prolonged exposure to hypersecretion of glucocorticoids may have adverse (neurotoxic) effects on the brain, particularly the hippocampus (9, 10), which plays a critical role in memory function, especially in the consolidation of short-term into long-term explicit memory, but also in the encoding of new information (11). Therefore, the severity and duration of depressive symptoms may lead to impairment of memory function.There are two other explanations for the association between depression and cognitive decline. First, a common underlying organic pathology, for instance, in white matter and other subcortical abnormalities (12), may cause depression as well as cognitive decline in elderly respondents. Second, depression may be considered as a psychological reaction to eroding cognitive capacities early in the course of dementia (4).In our former study (8), we investigated these three hypotheses on the association between late life depression