Multiple sclerosis and depression: influence of interferon beta therapy.

Background and Objectives: Depression is frequently part of the clinical picture of multiple sclerosis (MS). Major depression affects one in two patients with MS during the course of their lifetime. Our objectives were to determine first, whether interferon beta-1a (IFNbeta-1a) treatment increases the risk or level of depression and, secondly, whether depression status and depression evolution are related to the clinical characteristics of the disease.
Patients and Methods: We investigated 106 consecutive patients with relapsing remitting MS treated with IFNbeta-1a (Avonex). Patients with evidence of severe depression were excluded. The depression status, scored on the Beck Depression Inventory (BDI-II) (stratified as minimum, mild, moderate or severe level), and disability, scored on the Expanded Disability Status Scale (EDSS), were evaluated before and after 12 months of IFNbeta-1a treatment.
Results: At baseline, 85% of patients had a minimum or a mild depression status and after 12 months of treatment most of them (83%) retained their baseline status. Beck scores before and after treatment were not significantly different (P = 0.63). There was no correlation between age, gender, duration of illness or EDSS score and Beck score at baseline (P = 0.696). Patients with disability progression after one year of IFNbeta-1a treatment had a significantly higher Beck score at baseline than patients without disability progression (P = 0.003).
Conclusion: IFNbeta-1a (Avonex) does not seem to significantly influence the depression status of MS patients even in those with disability progression.