MICROSLEEP DURING PARTIAL SLEEP-DEPRIVATION IN DEPRESSION

Background: Sleep deprivation (SD) exerts a beneficial effect on mood and sleep in about 60% of depressed patients usually followed by a rel apse into depression after the recovery night. Short phases of sleepin ess, especially naps in the early morning, may be responsible for this phenomenon. Methods: To evaluate the effect of short, even ultrashort phases of sleep-microsleep (MS) during partial sleep deprivation (PSD ) on mood cognitive psychomotor performance (CPP), and sleep, an elect roencephalograph (EEG) was continuously recorded over 60 hours in 12 p atients with major depression. Subjective mood was assessed by a visua l analogue scale and CPP by a letter cancellation test. Results: The r esults illustrate that in depressed patients during PSD the amount of MS is increased, predominantly in the early morning, which was subject ively unrecognized and not observed by nursing staff Patients with a l ow cumulative amount of MS during PSD improved significantly in mood, CPP, and sleep pattern compared to the patients with a high amount of MS who showed only slight changes. Conclusion: Therefore, accumulated MS may influence the SD-induced positive effects in depressed patients . (C) 1998 Society of Biological Psychiatry.