Temporal ordering of subjective cognitive decline and depressive symptoms in a multiracial community cohort

Abstract

AbstractBackgroundSubjective Cognitive Decline (SCD), a proposed marker of preclinical Alzheimer’s disease (AD), is commonly associated with depressive symptoms. However, the basis and directionality of this association is unclear. Divergent hypotheses propose that mood changes either cause SCD or represent a psychological reaction to perceived cognitive decline. Alternatively, mood and SCD may both be part of a dementia prodrome. Longitudinal evaluation is critical to understand the temporal ordering of SCD and depressive symptoms. Further, given known differences in the prevalence of depressive symptoms across sex‐ethnoracial groups, it is important to examine temporality across these groups.Methods3365 (68% women, 75 (SD=6) years old, 10 (SD=5) years educated) participants without dementia at baseline were included in this study. Of these, 1005 were non‐Hispanic Black, 1450 Hispanic and 910 non‐Hispanic White. Depressive symptoms were measured using the Center for Epidemiological Studies Depression scale (CES‐D). SCD was assessed with a 9‐item questionnaire assessing memory difficulties. Separate autoregressive generalized additive mixed effects models (GAMMs) were conducted. Each model included a lagged cross‐symptom variable, an autoregressive same‐symptom variable, and a within‐visit association between CES‐D and SCD. Models additionally included age, time in study, dementia status, education and objective memory performance. Primary coefficients of interest were lagged cross‐symptom effects, estimated across and within sex‐ethnoracial groups.ResultsWhole‐sample results showed similar coefficients for models of SCD predicting depressive symptoms (b=.021, p=.021) and models of depressive symptoms predicting SCD (b=.045, p=.001; Figure 1). Stratified analyses showed that within Black participants, depressive symptoms preceded SCD (b=.098, p<.001) whilst the opposite pattern was seen in Hispanic participants (b=.025, p=.027). With regard to sex, depressive symptoms preceded SCD in men, particularly white men (b=.141, p=.004). In contrast, SCD preceded depressive symptoms in women, primarily Hispanic women (b=.030, p=.019).ConclusionsResults provide evidence for bidirectionality between depressive symptoms and SCD, underscoring the multiple pathways by which these two factors are linked in the course of cognitive aging. However, stratified results reveal nuanced patterns between depressive symptoms and SCD across sex‐ethnoracial groups that may offer clues to the relevance of SCD as a marker of pre‐clinical AD in different populations.