Affective reserve in older adults with and without multiple sclerosis: A residual-based approach

The concept of affective reserve has been proposed, but not operationalized, as a buffer designed to regulate mood and behavior in response to adverse events. This study derived a residual-based metric of affective reserve and evaluated whether it mediated associations between having multiple sclerosis and subjective well-being in older adults.

Sociodemographics and brain pathology metrics were regressed against a composite mood, extraversion, and consciousness variable to derive affective reserve in a sample of older adults with multiple sclerosis (n = 107) and without (n = 104). Linear regressions were run to examine the associations between affective reserve and well-being, measured with the Short Form-12 Mental Composite Summary and Physical Composite Summary. Hayes' PROCESS was used to evaluate affective reserve as a mediator between group status and well-being.

Affective reserve was positively associated with both Mental Composite Summary and Physical Composite Summary. After covariate adjustments, affective reserve fully mediated the relationship between having multiple sclerosis and Mental Composite Summary (b = 1.350, 95% confidence interval: 0.142-2.591) and partially mediated the association between multiple sclerosis and Physical Composite Summary (b = 0.915, 95% confidence interval: 0.073-1.906).

This residual-based metric offers a novel approach for measuring affective reserve. Not only is it associated with both physical and mental well-being, but it explained the relationship between the latter and the presence of multiple sclerosis.