Depressive Symptoms as a Mediator of the Association Between Functional Social Support and Executive Function: A Moderated Mediation Analysis of the Canadian Longitudinal Study on Aging’s Comprehensive Cohort

Abstract

BACKGROUND: Social support and depression are modifiable factors that can affect cognition. Social support and depression may be related through the influence of close relationships on emotional regulation; however, few studies have investigated whether depression mediates the relationship between social support and key domains of cognition, such as executive function. OBJECTIVES: To explore whether depressive symptoms mediate the association between functional social support and executive function, and to ascertain if age and sex moderate this mediation. METHODS: Analyses were based on baseline and three-year follow-up data (n=16,421) from the Comprehensive cohort of the Canadian Longitudinal Study on Aging, a population-based study of adults aged 45–85 years at baseline. Baseline functional social support was measured with the Medical Outcomes Survey-Social Support Survey, follow-up executive function with a combined z-score of five cognitive tests, and follow-up depressive symptoms with the 10-item Centre for Epidemiological Studies Depression Scale. Conditional process analysis, a robust strategy based on a linear regression framework, was used to evaluate moderated mediation. RESULTS: After adjusting for sociodemographic, health, and lifestyle covariates, depressive symptoms at baseline significantly mediated the association between functional social support and executive function. This mediated effect was significant across most age and sex subgroups, with the exception of males and females 65–74 years old. CONCLUSION: At least some of the benefits of social support on executive function depend on the positive effects of social support on depressive symptoms. Social support interventions with components addressing depression may be effective at promoting executive function in middle-aged and older adults.