The Relationship Between Chronic Fatigue Syndrome and Depression: Mediating Roles of Executive Functions in Patients With Relapsing-Remitting Multiple Sclerosis

Objective: This study aimed to investigate the relationship between chronic fatigue syndrome (CFS) and depression with the mediating role of executive functions (EFs) in patients with relapsing-remitting multiple sclerosis (RRMS). Methods: The statistical population of this descriptive correlational study included all patients with RRMS who were referred to Tehran neurologists in the summer of 2021 and among them, 208 samples who were eligible to enter the study, were selected via available sampling methods. To collect data, Krupp et al.'s (1988) fatigue severity scale (FSS), Nejati's cognitive abilities (NCA), and Beck depression inventory (II-BDI) were used. Pearson correlation method and structural equation modeling (SEM) were used to analyze the data. Results: Of seven subscales of EFs, the subscales of working memory, inhibitory control, selective attention, planning, and cognitive flexibility, which are called "cold" processes of EFs, were approved as mediators at the level (P<0.001), but the subscales of cognitive functioning, decision-making, and controlled attention, which are hot functions and require emotional awareness and regulation of personal social behaviors and decision-making with emotional and personal interpretation and empathy, were not approved as mediating roles. The results also showed that in patients with RRMS, there was a significant relationship between CFS and depression, between CFS and EFs, and between EFs and depression (P<0.001). Conclusion: The results of the present study can be used in cognitive rehabilitation to improve EFs and consequently improve depression in patients with MS.