Cognitive Reserve Attenuates the Effect of Disability on Depression in Multiple Sclerosis

Objective: The current study explored the moderating role of cognitive reserve on the relationship between disability and depression in a sample of individuals in which brain pathology is thought to contribute to depression (multiple sclerosis; MS). Method: Fifty-four individuals with MS were examined. Depression was measured using the Beck Depression Inventory-Fast Screen (BDI-FS). In addition to collecting demographic (education) and disease burden (Expanded Disability Status Scale; EDSS) related variables, participants completed a neuropsychological test battery and psychosocial questionnaires. Cognitive reserve (CR) was conceptualized in two ways: Fixed CR and Malleable CR. Fixed CR was measured using years of education and crystallized intelligence (Shipley Vocabulary). Malleable CR was operationalized as a composite of measures from the Cognitive Heath Questionnaire (CHQ). Two regressions on depression (BDI-FS) examining either type of cognitive reserve, EDSS, and their interactions were explored. Results: The interaction between EDSS and both conceptualizations of cognitive reserve were significant, t(50) = -2.60, p = .013, PRE = .12 (Fixed CR); t(47) = -2.02, p = .049, PRE = .08 (Malleable CR). Simple effects testing revealed the same pattern regardless of the type of cognitive reserve examined; EDSS predicted depression only in those with low cognitive reserve. Conclusions: Cognitive reserve moderates the relationship between disability and depression in MS; disability does not appear to influence depression in those with high cognitive reserve.