Systematic review of depression in patients with multiple sclerosis and its relationship to interferonβ treatment.

Multiple sclerosis is a chronic disease considered the major cause of neurological disability in young adults worldwide. While depression is considered a determinant factor of impaired quality of life and poorer prognosis among patients with multiple sclerosis, it is very often dismissed and undertreated by physicians. Depression has been related to treatment with some immunomodulatory drugs, such as IFNβ. Data from patients who committed suicide during the pivotal study of interferon used as a disease modifying treatment in multiple sclerosis support this association. Moreover, there is plenty of evidence of neuropsychiatric toxicity caused by the use of IFNα as a treatment for other medical conditions. Although this link still remains relatively unknown, the presence of warnings regarding the possible relationship between depression and IFNβ led to restriction in medical indications in these patients. The purpose of this paper is to try to understand the reasons for an increased prevalence in depression in multiple sclerosis and to examine the impact that IFNβ treatment has on their mood.