Different effects of phenelzine treatment on EEG topography in waking and sleep in depressed patients

A novel approach to investigate the relationship between depression and changes in sleep-wake regulatory mechanisms used the monoamine oxidase inhibitor (MAOI) phenelzine that is known to suppress rapid-eye-movement (REM) sleep. Sleep architecture and EEG topography during wakefulness and sleep were studied in eight depressed patients before and after five weeks of treatment with phenelzine (30-90 mg/day), which induced a significant alleviation of depressive symptoms. Theta power (4.75-7.5 Hz) during a 5-min wake EEG prior to sleep increased two-fold during administration of phenelzine. REM sleep was almost completely eliminated. This latter effect was compensated by increased duration of stage 2, whereas total sleep time was not shortened. In non-REM sleep (stages 2, 3, and 4), treatment slightly reduced EEG power between 2.0-6.25 Hz and 8.5-13.75 Hz; power in the 16.75-25.0 Hz band increased. Activity in the delta band (2-0-3.25 Hz) tended to be reduced in the fronto-central derivation, but not in centro-parietal and parieto-occipital derivations. However, the Treatment X Derivation interaction was not significant. These data indicate that in contrast to wakefulness the effects of phenelzine treatment on the EEG in non-REM sleep were small. Rank correlation analyses revealed no association between the antidepressant treatment response and the changes in sleep and EEG power spectra during administration of phenelzine. (C) 2002 American College of Neuropsychophannacology. Published by Elsevier Science Inc.