A-80: Depression as a Risk Factor for Alzheimer’s Disease: Evidence From Longitudinal, Neuropsychological, and Cross-Cultural Studies

Abstract

Objective: This review examines the relationship between depression and the development of Alzheimer’s disease (AD) in older adults, evaluating its impact on cognitive decline and neuropsychological functioning. The goal is to clarify the role of late-life and chronic depressive symptoms in the progression of AD, with implications for early intervention. Method/Data Selection: Data sources included peer-reviewed studies from 1996 to 2025, from PubMed, PsycINFO, and Web of Science, using terms such as “depression,” “major depressive disorder,” “Alzheimer’s disease,” and “cognitive decline”. Studies were selected based on inclusion criteria of (a) ages 60+, (b) standardized depression scales, (c) longitudinal designs reporting AD incidence or mental health outcomes. Ten studies met these criteria, with sample sizes ranging from 40 to 47,555 participants from the United States, China, and various European countries. Results/Data Synthesis: Across neuroimaging and neuropsychological assessments, depressive symptoms positively correlate with cognitive decline and AD incidence (e.g., Wilson et al., 2002; Chen et al., 2008; Xu et al., 2025). Depression severity correlated with hippocampal atrophy and increased amyloid plaques (Hofrichter et al., 2014; Sheline et al., 2003). In advanced AD, informant-reported depression was more predictive of cognitive impairment, compared to self-reports (Gold et al., 2020). In addition, environmental stressors, such as COVID-19, exacerbated depressive symptoms (El Haj et al., 2025). Conclusions: Depression is a significant risk factor for AD, with severity, late-onset, and environmental causes amplifying this risk. Assessing depressive symptoms in older adults may be an early indicator of AD susceptibility. Future studies should examine mechanisms linking depression to AD pathology and evaluate whether timely treatment of depression mitigates AD progression.