Systematic review of the association between interferon treatment and depression in patients with multiple sclerosis

Introduction Multiple sclerosis (MS) is a common chronic neurological disease. Interferon beta (INF-1b) was the first disease-modifying drug to be approved for the treatment of multiple sclerosis. During INF-1b pivotal trials, an association to depression was found. Later, in a study about its efficacy, three suicide attempts were accounted. Objectives Depression lifetime prevalence in MS patients is 50%, almost three times the rate in the general population. Suicide rate is also significantly higher. Depression has the greatest impact on quality of life. Besides MS treatment, depression itself may be related to neuronal damage, immune dysfunction and lifestyle changes. Aims The aim of this review is to assess the relationship between INF-1b and depression risk in MS patients. Methods We performed a literature search on PubMed database using the following keywords. depression, multiple sclerosis, interferon treatment. We included only human studies in English for the past five years. The abstracts were reviewed and also the full text when necessary. Results We selected 8 articles. Regarding their design, there was 1 cross-sectional study, 1 retrospective analyses, 1 clinical trial, 1 case control-study and 3 cohort studies. No meta-analyses or previous reviews were found. Two of the studies showed a prejudicial effect, three found no differences and three reflected a beneficial effect. Conclusions In conclusion, the link between INF-1b and depression is uncertain. Although some studies have found direct relationship, recent publications have seen no changes in mood, and even a positive effect. Studies' limitations are remarkable, which is why further investigation needs to be done.