Background: Behavioral symptoms, such as apathy and depression, are common in multiple sclerosis (MS) but their relationship with cognitive and clinical characteristics often remains underinvestigated and not monitored over time.
Objective: The aim of this study was to assess the evolution of cognitive profile of patients affected by MS in relation to apathy and depression using a 2-year follow-up study.
Methods: Two years after the first assessment, 100 of 125 MS patients were re-evaluated on a comprehensive neuropsychological battery, and on specific scales for assessment of apathy (Apathy Evaluation Scale-Self-reported) and depression (Hamilton Depression Rating Scale).
Results: After 2 years (T1), we found a relatively consistent prevalence of apathy (about 40%) and a reduction in prevalence of depression (from 44% to 30%). Higher level of apathy at baseline predicted the progressive cognitive changes at follow-up; and patients with apathy without depression ("pure" apathy) than patients without apathy had poorer performance on the interference task of the Stroop test assessing inhibitory control.
Conclusion: The present results suggested that apathy in MS was associated with more severe executive dysfunctions (in particular cognitive control). Apathy rather than depression predicted cognitive impairment in MS over time.
Keywords: Multiple sclerosis; apathy; behavioural disorders; cognitive deficits; cognitive dysfunctions; depression.