Effects on Sleep and the Electroencephalogram

BZs are often taken to induce sleep, but in reality, they cause a disturbed sleep pattern. Disturbances in sleep patterns are a major source of abnormal emotional and behavioral reactions. 

The effects of the BZs on the electroencephalogram (EEG) resemble those of other sedative/hypnotic agents, including decreased alpha activity and increased low-voltage fast activity, especially beta activity (Rail, 1990). Their effects on sleep are also similar to those of other CNS depressants and provide a window into the dysfunctions they produce (Rail, 1990). 

Before the brain rebounds after one or more doses, the BZs decrease sleep latency (the time it takes to fall asleep) and reduce the number of awakenings. The overall time in REM sleep is usually shortened, but the number of cycles of REM may be increased later in sleep. Total sleep duration is usually increased. There are complex effects on the dream process. 

Within a short time of starting Halcion, rebound begins to dominate the clinical picture, and insomnia worsens. Nishino et al. (1995) observed that short-acting BZs were initially preferred for elderly patients. They remarked, However, it has since been found that short-acting BZs induce rebound insomnia (a worsening of sleep beyond baseline levels on discontinuation of a hypnotic), rebound anxiety, anterograde amnesia, and even paradoxical rage.  

In general, the usefulness of BZs in insomnia is temporary at best. They do not provide for normal sleep, but rather for a disruption in various aspects of the normal cycle. 

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