Background: Interferon (IFN) beta is a safe and efficient drug for treating multiple sclerosis (MS). It is widely accepted that previously depressed patients may get worse when using IFN-beta. There are few reports on the association of IFN-beta and severe depression among patients without previous psychiatric history.
Methods: Discussion of a case of a patient with MS who developed severe depression and attempted suicide while using IFN-beta encouraged us to review the subject. A group of neurologists in Brazil retrospectively gathered together their similar cases for the present paper.
Results: The present paper reports on 11 cases of severe depression with suicide attempts or ideation among patients with MS who were using IFN-beta. These patients had no previous history of any psychiatric disease. Nine patients developed the symptoms over a relatively short period (4 months, on average). Two patients developed severe depression after more than 1 year of treatment with IFN-beta. Phobic, aggressive, behavioral, psychotic, and manic symptoms also were observed in these patients, thus suggesting the existence of a complex mood-behavior disorder associated with this drug. Interferon beta withdrawal led to complete remission of symptoms. The Naranjo algorithm established a highly probable association between IFN-beta and this adverse reaction in these patients.
Conclusions: Although uncommon, severe depression with suicide ideation or attempts may be observed during treatment of MS with IFN-beta. This association should not discourage the use of this drug, but physicians need to be aware of this possible adverse event from IFN-beta.