Evaluation of emotional disorders before and during treatment with interferon beta in patients with multiple sclerosis.

Background: Domains encompassing emotional disorders in relapsing-remitting MS (RRMS) patients are still unclear.

Methods: We performed a 24-month, multicenter, single-arm, prospective study. RRMS patients started IFN-β treatment at baseline. The primary endpoint was lack of emotional control, measured using the "Echelle d'HumeurDépressive" (EHD) scale three times at baseline and at 10 post-treatment visits. Secondary endpoints were emotional blunting, irritability, fatigue, depression and anxiety. A linear mixed covariance model assessed change from baseline on an intention-to-treat basis, under the assumption of no mood disorder effect (one-sided 97.5% level), in which autoregressive type of autocorrelation was tested.

Results: Out of 79 recruited patients, 70 were analyzed: 80% female; mean (SD) age, 37.0 (11.5) years. Mean (SD) lack of emotional control score at baseline and Month 24 was 12.7 (4.4) and 12.6 (5.5), respectively, versus 10.1 (3.2) in a healthy control population matched for age and sex. Stepwise analysis identified younger age, male sex and antidepressant use as significant predictors of higher lack of emotional control values.

Conclusions: Based on 24 months of prospective follow-up, the results of this study highlights a broad spectrum of emotional disorders in the MS population at the time of disease modifying drugs initiation but no major IFN-β-related emotional disorders (mood dyscontrol, anxiety, depression) were observed. However, sporadic occurrences of severe mood disorders and suicidality cannot be excluded.