Older person behavioral and psychological symptoms (BPS) and functional limitations mediate the association between older person cognitive impairment and depressive symptoms in the caregiver

We assess for the mediation of the association between older person cognitive impairment and caregiver depressive symptoms through older person BPS and functional limitations, and whether the mediation varies by caregiver–older person relationship (spouse/adult child). Data for 1111 older person (aged 75+ with activity of daily living (ADL) limitation)–caregiver dyads from Singapore were used. The outcome variable was dichotomous (caregiver clinically significant depressive symptoms [CSDS]: yes/no) in the primary analysis and continuous (caregiver depressive symptoms score) in the sensitivity analysis. The causal steps approach assessed for the mediation of the association between older person cognitive impairment (yes/no) and the outcome variable through the two potential mediators. A bootstrapping approach calculated point estimates and confidence intervals (CIs) of the indirect (∼mediated) effects. Variation of the indirect effects by caregiver–older person relationship was also assessed. In the primary analysis, the causal steps approach supported older person BPS and functional limitations as mediators. The bootstrapping approach confirmed both as significant mediators, though BPS (indirect effect odds ratio (OR) 1.32 [95% bootstrap CI 1.19,1.48]; %mediation: 70.6%) was a stronger mediator than functional limitations (1.04 [1.01,1.11]; %mediation: 11.5%). Variation of the indirect effects by caregiver–older person relationship was not supported. Results of the sensitivity analysis confirmed these results. We conclude that while caring for an older person with cognitive impairment is detrimental for the caregiver's mood, management of associated BPS and functional limitations, especially the former, among such older persons may reduce depressive symptoms among their caregivers. Spouse as well as adult child caregivers benefit.