Effect of chronic phenelzine treatment on REM sleep: report of three patients.

Antidepressants belonging to the class of monoamine oxidase inhibitors (MAOI) such as phenelzine have long been known to drastically suppress REM sleep. Sleep and the electroencephalogram (EEG) in sleep and waking were studied in three depressed patients at regular time intervals before, during and after 6 to 18 months of phenelzine treatment. While REM sleep was initially eliminated in all patients, short REM sleep episodes reappeared after three to six months of medication. Total sleep time and EEG slow-wave activity (SWA, spectral power within 0.75-4.5 Hz) in nonREM sleep (stages 1-4) were not changed. In contrast, EEG theta frequency activity (TFA, power within 4.75-8.0 Hz) during a 5-min wake interval recorded prior to the sleep episodes was initially enhanced, and tended to correlate negatively with the percentage of REM sleep (p =.06). This observation indicates that compensatory REM sleep mechanisms may occur in wakefulness during chronic MAOI treatment.