The effect of mood and cognition on relationship between sleep disturbances and fatigue in people with multiple sclerosis

Fatigue is one of the most common symptoms in people with multiple sclerosis (MS) which reduces quality of life in these people. Sleep disorders are also common in people with MS. In order to facilitate management of fatigue and sleep disorder in this group of patients, it is important to determine those factors that are affecting them. Since mood disorders (depression and anxiety) and cognitive impairment is common in patients with MS, it seems sensible to examine the possible impacts of these factors on the relationship between sleep disorder and fatigue. Therefore, the aim of this study was to investigate the effect of mood disorder and cognitive impairment on the relationship between sleep disorder and fatigue in MS patients.
There were sixty people with MS participated in this study with an average age of 35 years who were mostly women (87%). They completed Pittsburg Sleep Quality Index (PSQI), Modified Fatigue Impact Scale (MFIS), Mini-mental State Examination (MMSE), The Hospital Anxiety and Depression Scale (HADS) questionnaires
Depression and cognitive status were the most effective factors related to fatigue and were producing 48.8% of the variation in fatigue. Other variables such as anxiety and sleep disorders had less effect. There was a positive relationship between sleep disorders and fatigue. Mood and anxiety scores were significantly and positively correlated with sleep disorders (P Anxiety, depression and sleep disorder are the most important factors that influence fatigue. It is necessary for therapist to consider treatments for depression and anxiety in order to manage sleep disorders in people with MS.