AUTHOR=Penner Iris-Katharina , Sivertsdotter Eva Catharina , Celius Elisabeth G. , Fuchs Siegrid , Schreiber Karen , Berkö Sara , Svenningsson Anders , for the TYNERGY trial investigators TITLE=Improvement in Fatigue during Natalizumab Treatment is Linked to Improvement in Depression and Day-Time Sleepiness JOURNAL=Frontiers in Neurology VOLUME=Volume 6 - 2015 YEAR=2015 URL=https://www.frontiersin.org/journals/neurology/articles/10.3389/fneur.2015.00018 DOI=10.3389/fneur.2015.00018 ISSN=1664-2295 ABSTRACT=Background: Fatigue is a frequent symptom in multiple sclerosis (MS) and often interrelated with depression and sleep disorders making symptomatic treatment decisions difficult. In the single-arm, observational phase IV TYNERGY study, relapsing-remitting MS patients showed a clinically meaningful decrease in fatigue over one year of treatment with natalizumab. Objective: To evaluate whether fatigue improvement might be directly linked to improved depression and daytime sleepiness. Methods: Patients were assessed regarding fatigue, depression, and daytime sleepiness. The relation between changes of the two latter symptoms and changes in fatigue was analysed. Results: After one year of natalizumab treatment, the majority of patients (>92%) remained stable or improved in total, motor and cognitive fatigue. Proportion of patients without depression increased by 17% while proportions of mildly depressed patients or patients with potential major depression decreased by 5% and 12%, respectively. Proportion of patients classified as not being sleepy increased by 13% while proportions of sleepy and very sleepy patients decreased by 11% and 2%, respectively. Most importantly, improved depression and sleepiness were significantly related to improved fatigue. Conclusion: Our findings highlight the importance of patient-reported outcomes in identifying potential benefits of drug treatment beyond its well-established effects on disease activity and disability progression.