The emergence of depressive symptoms in late life: the importance of declining health and increasing disability.

Despite considerable progress in the epidemiology of late life depressive disorders, the determinants and course of late life depressive symptoms remain unclear. The apparent reciprocal relationship between depression and disability, a consistent finding in cross-sectional studies further confounds efforts to estimate the importance of depressive symptoms in the elderly. In a longitudinal study of 1457 aged community residents who completed the Center for Epidemiologic Studies Depression scale at baseline and 24 months later, a significant level of depressive symptoms emerged in 163 respondents (11%), while 1080 (74%) remained symptom free. Unlike other studies, we found that the number of medical conditions, social support, life events, and demographic characteristics contributed little to distinguish those with emerging symptoms from those who remained symptom free. However, increasing disability and declining health preceded the emergence of depressive symptoms and accounted for seventy percent of the variance explained by discriminant analysis. These findings have etiologic implications for both the course and determinants of depression in late life.