induced psychopathology

To the editor: Psychiatric comorbidity is reported in 9 to 37 % of patients treated with recombinant interferon (1). Recently, diminis-hed serotonergic neurotransmission has been proposed as the pathophysiological mechanism (2). Treatment of these side-effects focuses on serotonin specific reuptake inhibitors (SSRIs). Prophylactic treatment with the SSRI paroxetine reduced the per-centage of patients developing depression from 45 % to 11 % (3). SSRIs may not be the drugs of choice in all patients. In a case report, the antidepressive effect of an SSRI was nullified by interfe-ron (4). As an alternative we prescribed mirtazapine, an antidepres-sant, with postsynaptic actions on the serotonergic and noradrener-gic systems, which acts independent of available serotonin. Thus far 3 patients have been treated. The first patient was a 43 years old female with multiple sclerosis. After 6 weeks treatment with interfe-ron-beta (24 million U/week subcutaneously) depression and increa