Longitudinal Relationships Between Subjective Cognitive Decline and Objective Memory: Depressive Symptoms Mediate Between-Person Associations

Article type: Research Article

Authors: Hill, Nikki L.^{a; *} | Bhargava, Sakshi^a | Bratlee-Whitaker, Emily^a | Turner, Jennifer R.^b | Brown, Monique J.^{c; d; e; f} | Mogle, Jacqueline^b

Affiliations: [a] College of Nursing, Pennsylvania State University, University Park, PA, USA | [b] Edna Bennett Pierce Prevention Research Center, Pennsylvania State University, State College, PA, USA | [c] Department of Epidemiology and Biostatistics, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA | [d] South Carolina SmartState Center for Healthcare Quality, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA | [e] Rural and Minority Health Research Center, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA | [f] Office of the Study on Aging, Arnold School of Public Health, University of South Carolina, Columbia, SC, USA

Correspondence: [*] Correspondence to: Nikki Hill, PhD, RN, 201 Nursing Sciences Building, University Park, PA, 16802, USA. Tel.: +1 814 867 3265; E-mail: nikki.hill@psu.edu.

Abstract: Background:Subjective cognitive decline (SCD) may be an early indicator of cognitive impairment, but depressive symptoms can confound this relationship. Associations may be influenced by differences between individuals (i.e., between-persons) or how each individual changes in their experiences over time (i.e., within-persons). Objective:We examined depressive symptoms as a mediator of the between- and within-person associations of SCD and objective memory in older adults. Methods:Coordinated analyses were conducted across four datasets drawn from large longitudinal studies. Samples (range: n = 1,889 to n = 15,841) included participants 65 years of age or older with no dementia at baseline. We used multilevel structural equation modeling to examine the mediation of SCD and objective memory through depressive symptoms, as well as direct relationships among SCD, objective memory, and depressive symptoms. Results:Older adults who were more likely to report SCD had lower objective memory on average (between-person associations), and depressive symptoms partially mediated this relationship in three of four datasets. However, changes in depressive symptoms did not mediate the relationship between reports of SCD and declines in objective memory in three of four datasets (within-person associations). Conclusion: Individual differences in depressive symptoms, and not changes in an individual’s depressive symptoms over time, partially explain the link between SCD and objective memory. Older adults with SCD and depressive symptoms may be at greater risk for poor cognitive outcomes. Future research should explore how perceived changes in memory affect other aspects of psychological well-being, and how these relationships influence cognitive decline and Alzheimer’s disease risk.

Keywords: Aging, cognition, depression, memory

DOI: 10.3233/JAD-210230

Journal: Journal of Alzheimer's Disease, vol. 83, no. 4, pp. 1623-1636, 2021