Sleep Continuity

BzRAs significantly reduce sleep latency and the number and duration of awakenings, resulting in increased total sleep and improved sleep continuity. 

A measure used to assess sleep quality, usually determined by means of polysomnography. A parameter such as wake after sleep onset (WASO) is often used to describe sleep continuity. 

Winokur A., Sateia M. J., Boyd Hayes J. el al. (2000). Acute effects of mirtazapine on sleep continuity and sleep architecture in depressed patients a pilot study. Biol. Psychiatry 48, 75-7. 

Polysomnographic sleep research has demonstrated that besides disturbances of sleep continuity in depression, sleep disturbance is also characterized by a reduction of slow-wave sleep and a disinhibition of REM sleep, with a shortening of REM latency, a prolongation of the first REM period, and increased REM density [62]. Most effective antidepressant agents suppress REM sleep, and depressive symptoms are at least transiently alleviated by manipulations of the sleep-wake cycle, such as sleep deprivation or a phase advance of the sleep period [63]. Thus, there appears to be a bidirectional relationship between sleep, sleep alterations and mood. 

These factors include sleep, continuous hours of wakefulness, circadian rhythms, and sleep disorders. 

Taken together, these findings suggest that while a nap on the order of 5 min may produce some benefit, consistent benefits are achieved by a nap of 10 min duration. This conclusion is supported by Bonnet (47), who investigated the effects of sleep continuity and the recuperative benefits of different-length sleep periods and concluded that continuous sleep periods longer than 10 min are required for sleep to have recuperative value. 

Stein MB, Enns MW, Kryger MH (1993) Sleep in nondepressed patients with panic disorder II. Polysomnographic assessment of sleep architecture and sleep continuity. J Affect Disord 28 1-6... 

The present section brings some support to the notion that a deficient NREM-promoting system may underlie sleep disturbances in depressive disorder. These arguments are not at variance with those of the preceding section since hypotheses of hyperarousal and of Process S deficiency are not mutually exclusive both together or separately could explain sleep continuity disturbances and SWS deficit observed in depressive illness. 

The PSG withdrawal effects of zopiclone (7.5 mg), zolpidem (10 mg) and triazolam (0.25 mg) as compared with placebo were studied in 38 healthy subjects over 4 weeks [33], Slight, non-significant rebound effects on sleep continuity were detected after withdrawal of zopiclone and zolpidem. Total sleep time and sleep efficiency were lower the first night after cessation of triazolam. 

Clinical improvement of depression is frequently accompanied by a normalization of sleep continuity disturbance. Difficulties in falling asleep, maintaining sleep, and problems with early morning awakening are going down [38], while disturbance of sleep architecture (reduced SWS and REM latency) may persist even in successfully treated patients [39, 40]. 

GH secretion appears in a single peak during the first SWS episode [51]. In contrast, cortisol remains on a basal level during the first half of the night and increases in the second half of the night until awakening [51]. Experimental studies show that the application of cortisol increases SWS [52, 53], while the application of CRH decreases SWS and reduces sleep efficiency [54, 55]. Opposite effects have been observed with the application of GH, which reduces SWS [56], and GHRH which increases SWS and improves sleep continuity [57]. 

In performing such sleep-walking acts, these individuals are partially aroused, but still deeply asleep in respect of the upper brain. We know this from lab studies in which brain waves have been recorded. The high-voltage slow waves of deep sleep continue to be recorded while the individual sleep walks. One old wives tale about sleep walking holds that it is a mistake to wake the person, usually a young person, up from such episodes. The answer to that one is to go ahead and try . It is usually impossible, but don t worry about it because, if you can t do it or if you do succeed in waking them, there will be no adverse consequence whatsoever. 

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