Depressive symptoms precede memory decline, but not vice versa, in non-demented older adults.

OBJECTIVES: To determine whether depressive symptoms typically precede or follow memory declines.
DESIGN: An autoregressive latent trajectory model was used to examine the direction of the relationship between depressive symptoms and memory decline observed over 12 years.
SETTING: Washington/Hamilton Heights Inwood Columbia Aging Project, a community-based longitudinal study of aging and dementia in northern Manhattan. PARTICIPANTS: Older adults initially without dementia(n = 2,425). MEASUREMENTS: Memory composite scores were computed from three subscores of the Selective Reminding Test. Depressive symptoms were assessed using a 10-item version of the Center for Epidemiologic Studies Depression Scale. Analyses controlled for age, sex, recruitment wave,education, black race, and Hispanic ethnicity measured at baseline and chronic disease burden measured at each study visit.
RESULTS: Initial depressive symptoms predicted worse memory scores at the second study visit (B weight = − 0.03; P = .003) and accelerated memory decline over the entire study period (B weight = − 0.02; P = .03). Memory scores did not predict subsequent depressive symptoms.
CONCLUSION: These findings suggest that depressive symptoms precede memory decline, but not vice versa, in late life. This pattern of results is consistent with hypotheses that depression is a prodrome of dementia or a causal contributor to memory decline. Clinicians should be aware that depressive symptoms may represent an early indicator not only of dementia, as reported previously, but also of memory decline more generally.