The monoamine oxidase inhibitor antidepressant, phenelzine, will abolish the signs of REM sleep after a delay of days or weeks. In a study utilizing 22 patients suffering from endogenous depression, the time course of mood change was related to the time course of the induced REM sleep change. A period of placebo administration preceded administration of 60, 75, or 90 mg of phenelzine dihydrogen sulfate daily.
Patient self-ratings of mood were employed and independent judges selected the date of onset of sustained mood improvement with at least three out of four in agreement for nine of the patients. In these nine depressed patients, restoration of normal mood coincided with the delayed abolition of the signs of REM sleep.