Introduction: Multiple sclerosis is the most common chronic inflammatory demyelinating disease of the central nervous system, mainly affecting young people. A breakthrough in the treatment of multiple sclerosis was the introduction of immunomodulating drugs that affect the natural course of the disease as well as improve the quality of life of patients. Aim of the study: To establish a possible association between the level of cognitive disorders, fatigue, depression and the used immunomodulating treatment (disease-modifying treatment) in patients with the relapsing-remitting form of multiple sclerosis. Materials and methods: The research material consisted of 169 patients with multiple sclerosis (diagnosed according to the 2010 McDonald criteria) with the relapsing-remitting form of multiple sclerosis. The subjects were divided into two groups: the test group – receiving disease-modifying treatment (n = 132), undergoing immunomodulatory therapy, and the control group – untreated multiple sclerosis (n = 37), patients who did not receive immunomodulating therapy. Methods: multiple sclerosis patient registry – RejSM questionnaire; Beck Depression Inventory II (BD-II); postural function assessment – MMSE (Mini-Mental State Examination); FACIT quality of life (Functional Assessment of Chronic Illness Therapy – Fatigue; FACIT Fatigue Scale, FFS). Patients from both groups underwent tests (BD-II, MMSE, FFS) at two time points: at baseline (I) and after 12 months of immunomodulating treatment (II). Results: The post-hoc test (Tukey’s) showed a decrease in Beck Depression Inventory and FACIT-F scores which was statistically significant only in the disease-modifying treatment group. The results indicate that the use of interferon beta causes a significant reduction in depression (p < 0.0001) and fatigue (p < 0.0001) between the measured time points. The FACIT scores were significantly different between the time points for those treated with glatiramer acetate (p < 0.0001). In the case of MMSE evaluation, the patients receiving disease-modifying treatment did not differ significantly between the beginning and end of the study (p = 0.1210). Conclusions: The results of our research indicate that disease-modifying treatment used in patients with the relapsing-remitting form of multiple sclerosis has a beneficial effect in terms of improving their quality of life and reducing the symptoms of depression.

immunomodulating treatment, multiple sclerosis registry (RejSM), cognitive functions, depression, fatigue