Association of Childhood Friendship Experience and Depressive Symptoms Among Older Adults: A Causal Mediation Approach

Few studies to date have investigated the potential mechanisms linking childhood friendship experiences to late-life depressive symptoms. This study examines the association of childhood friendship experiences with depressive symptoms among older adults and the mediating effects of social disconnectedness and cognitive function. A retrospective cohort analysis was performed using longitudinal data from a sample of 8,745 participants aged 60 years and above in the China Health and Retirement Longitudinal Study from 2013 to 2018. The causal association of childhood friendship experiences with depressive symptoms and the mediating roles of social disconnectedness and cognitive function were estimated using marginal structural models and the inverse odds ratio weighting method. Mediation proportions and confidence intervals (CIs) were calculated using a bootstrap resampling method. Respondents with greater childhood friendship deficits were more likely to have depressive symptoms (odds ratio: 1.19, 95% CI: 1.11, 1.26) than those with more favorable friendship experiences during childhood. The causal mediation analysis revealed that social disconnectedness, cognitive function, and their combination partially mediated the association of childhood friendship experiences with depressive symptoms by 15.70% (95% CI: 8.66%-24.17%), 17.18 % (95% CI: 7.61%-30.00%), 28.35% (95% CI: 17.75%-42.56%), respectively. Friendship experiences during childhood were related to the risk of depressive symptoms in older Chinese adults; more importantly, social disconnectedness and cognitive function partially mediated this association. Thus, improving social engagement and cognitive function in older adults could alleviate the accumulated disadvantages due to childhood friendship deficits and help to improve their psychological well-being.