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Sleep disturbance

How is sleep related to schizophrenia?

People with schizophrenia may show disturbances in the amount or the quality of sleep they generally receive. Typically, sleep follows a characteristic pattern of four stages, where stage 1 is a state of drowsiness and early sleep, stage 2 comprises the largest component of the sleep cycle and is the first complete loss of awareness of the external environment, stage 3 is a deep slow-wave sleep, and the fourth stage is rapid eye movement (REM) sleep where muscle paralysis and memorable dreaming occurs. Sleep disturbance can be measured in many ways, including the total sleep time, the sleep latency (the length of time it takes from full wakefulness to sleep) and the sleep efficiency index (the amount of time spent asleep while in bed). Sleep latency can have varying definitions, particularly regarding the definition of “asleep” – some studies define this more strictly as the time from lights out until 10 consecutive minutes of stages 2, 3 or 4; while other studies define the latency more leniently as the time from lights out until the first signs of stage 2 sleep.

What is the evidence on sleep disturbance?

Moderate to low quality evidence suggests large effects of increased sleep latency, reduced sleep time, and reduced sleep efficiency in people with untreated schizophrenia compared to people without schizophrenia. Medium-sized effects were found for reduced stage 2 sleep in untreated patients. No differences were reported for stage 2 sleep, stage 4 sleep, slow wave sleep, or REM sleep ratios to total sleep time. No differences were found in REM latency.


March 2016

Page last updated: 3:02  5 September 2017

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