The mediating role of processing speed in the relationship between depressive symptoms and cognitive function in multiple sclerosis

ABSTRACTIntroduction: Although disorders of mood and cognition are frequently observed in multiple sclerosis, their relationship remains unclear. We aimed to investigate whether this mood–cognition relationship is mediated by inefficient processing speed, a deficit typically associated with mood symptomatology in the psychiatric literature and a common deficit observed in multiple sclerosis patients. Method: In this study, comprehensive cognitive data and self-reported mood data were retrospectively analyzed from 349 patients with relapsing remitting multiple sclerosis. We performed a bootstrapping analysis to examine whether processing speed provided an indirect means by which depressive symptoms influenced cognitive functioning, specifically memory and executive function. Results: We observed that processing speed mediated the relationship between depressive symptoms and measures of memory and executive function. Interestingly, exploratory analyses revealed that this mediational role of processing speed...