Saturday, March 07, 2015

Slow Wave Sleep Deprivation in Depression

Bill Yates
Brain Posts
21st December 2011

Sleep abnormalities commonly occur in depression and are included in the diagnostic criteria for the disorder.  Acute sleep deprivation temporarily improves the symptoms of major depression in approximately 50 to 60 percent of patients.  The mechanism for this effect is not well understood.

Sleep architecture abnormalities in depression include reduced REM latency (period of time from falling asleep to first REM period).  A significant amount of research has focused on REM sleep issues in depression.  However, other sleep architecture parameters including slow wave sleep may be involved in the pathophysiology of depression.

Eric Landsness and colleagues at the University of Wisconsin recently published a study of selective slow wave sleep deprivation in a group of subjects with major depression.  They noted previous evidence that an antidepressant effect of sleep deprivation in depression was associated with a high delta sleep ratio (percent of time spent in slow wave activity during first non-REM sleep cycle).  From this association, they developed a hypothesis that selective slow wave sleep deprivation may produce an antidepressant response.

To selectively interrupt slow wave sleep, the sleep architecture was dynamically monitored throughout the night using a technique called high-density EEG.  Slow wave sleep was interrupted by linking an audible tone during periods of slow wave sleep.  The sound was sufficient to disrupt slow wave sleep but not loud enough to produce awakening.  Subjects completed three overnight sleep sessions--a baseline session, a slow wave sleep deprivation session and a rebound session after sleep deprivation.

Slow wave sleep deprivation produced a statistically significant reduction in self-reported depression and researcher-administered depression ratings.  However, the magnitude of improvement in depression found in this cohort was small (self-report IDS decreased from 16.5 to 15.0 and Hamilton Depression Rating Scale-13 item reduced from 10.7 to 7.8.  Previous studies of overnight total sleep deprivation have produced greater improvement in measures of depression severity.

The reduction in depression symptoms correlated with measures of slow wave activity during the baseline and rebound sessions.

This study provides evidence for the feasibility of producing sleep deprivation specific to slow wave sleep phases.  Additionally, the study demonstrates the utility of high-density EEG to examine the effect of localized sleep EEG patterns in depression.

The antidepressant effects of sleep deprivation in depression unfortunately lasts for only a day or so.  This limits the clinical utility of this intervention for patient populations.  Nevertheless, understanding the sleep markers of depression and understanding the mechanism for the antidepressant effect of sleep deprivation may lead to improved treatment strategies.

Photo of sea gull from the author's files.

Landsness EC, Goldstein MR, Peterson MJ, Tononi G, & Benca RM (2011). Antidepressant effects of selective slow wave sleep deprivation in major depression: a high-density EEG investigation. Journal of psychiatric research, 45 (8), 1019-26 PMID: 21397252.

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