CLINICAL PHARMACOLOGY 2003 (PART 21C)

Treatment is justified if it has significantly improved their wellbeing and function. A combination of medication with psychological techniques is likely to be most beneficial, especially for resistant cases.Sleep disordersNORMAL SLEEPHumans spend about a third of the time asleep but why we sleep is not yet fully understood. Sleep is a state of inactivity accompanied by loss of awareness and a markedly reduced responsiveness to environmental stimuli. When a recording is made of the electroencephalogram (EEG) and other physiological variables such as muscle activity and eye movements during sleep (a technique called polysomnography), a pattern of sleep emerges, consisting of...
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CLINICAL PHARMACOLOGY 2003 (PART 21C) SLEEP DISORDERS 19treatment is justified if it has significantly improved Quiet sleep is further divided into four stages,their wellbeing and function. A combination of each with a characteristic EEG appearance, duringmedication with psychological techniques is likely which there is progressive relaxation of the musclesto be most beneficial, especially for resistant cases. and slower, more regular breathing as the deeper stages are reached. Most sleep in these deeper stages occurs in the first half of the night. During paradoxical sleep, the EEG appearance isSleep disorders similar to that of waking or drowsiness. There is irregular breathing, complete loss of tone of the skeletal muscles, and frequent phasic movementsNORMAL SLEEP particularly of the eyes, consisting of conjugateHumans spend about a third of the time asleep but movements which are mostly lateral but can also bewhy we sleep is not yet fully understood. Sleep is a vertical (hence the term rapid eye movement sleep);state of inactivity accompanied by loss of awareness most dreaming takes place in this stage.and a markedly reduced responsiveness to environ- The length of total sleep in a day varies betweenmental stimuli. When a recording is made of the 3 and 10 hours in normal subjects with an averageelectroencephalogram (EEG) and other physiolo- in the 20-45 year age group of 7-8 h. Sleep time isgical variables such as muscle activity and eye decreased in older subjects, to about 6 h in the overmovements during sleep (a technique called poly- 70 year age group, with increased daytime nappingsomnography), a pattern of sleep emerges, consisting reducing the actual night time sleep even more. Theof five different stages. This pattern varies from amount of time spent in each of the five stagesperson to person, but usually consists of four or five varies between subjects and particularly with age,cycles of quiet sleep alternating with paradoxical, with much less slow wave sleep in older people.or active, rapid eye movement (REM) sleep, with The number of awakenings after the onset of sleeplonger periods of paradoxical sleep in the latter half also increases with advancing age. A normal subjectof the night. A representation of these stages and has several short awakenings during the night, mostcycles over time is known as a hypnogram, and one of which are not perceived as awakenings unlessderived from a normal subject appears in Figure they last more than about 2 minutes. Probably there19.6, with paradoxical sleep depicted as the shaded will not be clear consciousness but subject mayareas. have occasional brief thoughts of how comfortable Fig. 19.6 Normal hypnogram 39719 PSYCHOTROPIC DRUGSthey feel or how pleased that its not time to get up • otheryet, with an immediate return to sleep. If during the sleep scheduling disorders (circadian rhythmshort period of waking some factor causes anxiety disorder)or anger, e.g. aircraft noise, partners snores or restless legs syndromedread of being awake, progress to full awakening periodic leg movements of sleep.and being remembered is much more likely. Themore times this happens the more subjectscomplain of an unrefreshing sleep. The time spentasleep as a percentage of the time in bed is used as ameasure of sleep efficiency (96% in the case shown in InsomniaFigure 19.6). One of the most common ways in which Insomnia is characterised by the complaint of poorinsomnia develops is by clock watching; subjects sleep, with difficulty either in initiating sleep orcheck the time on awakening, remember it and maintaining sleep throughout the night. It canrepeat this cycle many times during the night. occur exclusively in the course of another physicalRemembering the time o ...