Short and long term effects of mirtazapine and venlafaxine on sleep-EEG in patients with major depression

Mirtazapine is a novel antidepressant with sleep promoting effects. In an ongoing study we evaluated the short term (after one week of treatment) and long term effects (after six weeks) of mirtazepine on polysomnography in 6 patients with major depression in comparison to the polysomngraphic effects of venlafaxine.

Mirtazapine improved sleep continuity and increased NonREM-sleep. No shortening of REM-latency and no suppression of REM-sleep was observed. Improvement of sleep continuity was predominantly evident after short term application and in the first part of sleep. In contrast, under venlafaxine therapy REM-sleep remained tremendously reduced during the six weeks of treament, while SWS, predominantly stage 4 increased exclusively in the first sleep cycle until the end of the study.

These data suggest that mirtazapine exerts beneficial effects on sleep continuity and NonREM sleep without suppressing REM-sleep which clearly differ from the effects of venlafaxine concerning sleep continuity, sleep architecture and REM-sleep.