The Role of Apathy in the Association Between Depressive Symptoms and Subjective Cognitive Complaints

OBJECTIVES: Self-perceived cognitive difficulties are a potential early marker of Alzheimer's disease (AD), frequently co-occur with depressive symptoms. This has hindered consideration of these subjective cognitive difficulties as a risk factor for AD. However, accumulating evidence points to dissociations between specific depressive symptoms (i.e., apathy, affective or mood symptoms, and others), with some suggestion that apathy is particularly predictive of and more proximate to AD and may drive the relationship between depressive symptomatology and AD. This study examines whether apathy drives the association between depressive symptoms and subjective cognitive complaints (SCC). METHODS: 151 cognitively normal older adults (68% female, mean age 73 ± 7 years) completed a 20-item SCC questionnaire, the Apathy Evaluation Scale, and the Geriatric Depression Scale (GDS). RESULTS: Depressive symptoms (per GDS) were significantly associated with SCC (p = 0.008). However, affective symptoms (dysphoria, anxiety, hopelessness), were not statistically associated with SCC (p = 0.100), while apathy symptoms were (p < 0.001). In a mediation model, apathy mediated the relationship between depressive symptoms and SCC, accounting for 53% of the total effect, indicating that apathy may drive the relationship between depressive symptoms and SCC. When stratified by sex, the results remained significant for women only. CONCLUSIONS: These results underscore the relevance of apathy in pre-clinical stages of AD, such as SCC, particularly in women. Understanding the complex associations between SCC and depressive symptoms will help refine conceptualization of SCC as a risk factor for AD.