Course of depression during the initiation of interferon beta-1a treatment for multiple sclerosis.

OBJECTIVE: To examine the hypothesis that increases in depression after initiation of treatment with interferon beta-1a for multiple sclerosis can be explained as representing a return to pretreatment levels of depression. DESIGN: Level of depression in patients with multiple sclerosis was assessed at 3 time points: 2 weeks before initiation of interferon beta-la treatment, at initiation of treatment, and at 2-month follow-up. SETTING: A health maintenance organization. PATIENTS: Fifty-six patients with confirmed relapsing forms of multiple sclerosis. MAIN OUTCOME MEASURE: The depression-dejection scale of the Profile of Mood States. RESULTS: Patients who scored high on the depression measure 2 weeks before the initiation of interferon beta-1a treatment showed significant reduction in depression at the initiation of treatment. However, depression returned nearly to initial levels within 2 months. CONCLUSIONS: These findings suggest that increases in depression after initiation of interferon beta-1a treatment are related to level of depression 2 weeks before initiation of treatment. Physicians should assess history of depression for all patients in whom interferon beta-1a treatment is initiated. Patients with a recent history of depression are at risk for increased depression within 2 months after starting interferon beta-1a treatment, even though they may not be depressed at the time of treatment initiation.