Depressive symptoms as a predictor of memory decline in older adults: A longitudinal study using the dual change score model.

Teles, Mariana; Shi, Dingjing

The directionality of the longitudinal association between depressive symptoms and memory remains a topic of intense debate. A unidirectional association where depression impacts the change in memory (or vice-versa) and a bidirectional association where the trajectories of both dimensions affect each other lead to different clinical implications. METHOD This study investigated the depression-memory longitudinal association in a sample of 2057 older adults aged between 60 and 99 years old from the Virginia Cognitive Aging Project. The bivariate dual change score model was used to investigate the directionality of the association between episodic memory and three dimensions of depression (somatic symptoms, depressed affect, and positive affect) throughout ten years (five measurement points), controlling for education and sex. RESULTS the bidirectional model showed the best fit between somatic symptoms and memory, with a significant coupling effect observed from initial somatic symptoms to subsequent changes in memory. For depressed and positive affect, the unidirectional model with initial levels of depression predicting following changes in memory showed the best fit to the data, with significant coupling effects observed. Higher initial levels of somatic symptoms and depressed affect predicted a subsequent decline in memory, and higher initial levels of positive affect predicted subsequent better memory performance. Statistical adjustments for covariates (education and sex) had no significant influence on these associations. CONCLUSIONS Our findings support a unidirectional association with higher depressive symptoms preceding a steeper decline in memory in older adults. We discuss the clinical implications for depressive symptoms as a predictor of subsequent memory decline.