Memory decline and depressive symptoms in a nationally representative sample of older adults: the Health and Retirement Study (1998-2004).

BACKGROUND/AIMS: Inconsistencies in the relationship between depression and cognitive decline may exist because the expected cognitive domains at risk have not been specified in previous study designs. We aimed to examine the relationship between depressive symptoms and verbal episodic memory functioning over time.

METHODS: Data from a prospective cohort study (Health and Retirement Study; 1998-2004; n = 18,465), a multistage national probability sample of older adults in the United States, were analyzed. Verbal learning and memory of a 10-word list learning task were the main outcomes. Depressive symptoms (Center for Epidemiologic Studies - Depression Scale) constituted the main predictor.

RESULTS: Depressive symptoms were associated with significantly lower immediate (-0.05; p < 0.001) and delayed (-0.06; p < 0.001) word list recall scores after controlling for demographics and baseline and time-varying cardiovascular disease risks and diseases.

CONCLUSIONS: In this US national study of older adults, elevated depressive symptoms were associated with declines in episodic learning and memory over time. These associations were little affected by the demographic or medical conditions considered in this study. The results suggest that learning and memory decline may be a long-term feature associated with depressive symptoms among the nation's older adult population.