Background: Recent side effect data from clinical trials of interferon beta in multiple sclerosis (MS) have failed to confirm that these medications are associated with an increased risk of depression. However, these studies have used highly selected samples and the results may not be generalizable to real world settings.
Methods: Clinical data on subjects from southern Alberta who have applied for, or are receiving, public reimbursement for MS treatment are maintained in a database at the University of Calgary Multiple Sclerosis Clinic. Depression ratings obtained using the Center for Epidemiological Studies Depression Rating Scale (CES-D) are included in this database. In the current analysis, these longitudinal data were used to determine whether depressive symptoms were associated with disease-modifying treatments.
Results: At baseline, ratings were available for 163 subjects. Those choosing interferon beta resembled those choosing glatiramer acetate in most respects. During follow-up, no differences were observed in the prevalence or incidence of depression and CES-D scores were not found to differ between the treatment groups.
Conclusions: The failure to identify higher rates of depression both in previous intervention studies and in the current observational study provides confirmation that these drugs are not substantially associated with the occurrence of depression.