Sleep disturbance

What is sleep disturbance?

People with a mental illness may show disturbances in the amount or quality of sleep they 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 memorable dreaming and muscle paralysis 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 for sleep disturbance?

Moderate to high quality evidence suggests large effects of more time in bed, but poorer sleep quality in people with bipolar disorder than controls. There are medium-sized effects of more sleep time (particularly stage 1), but more awakenings, and small effects of more sleep latency in people with bipolar disorder. Results were similar in euthymic or mood phases of the disorder.

Compared to people at familial or clinical risk of bipolar disorder, moderate quality evidence suggests a medium-sized effect of lower relative amplitude of the sleep-wake cycle in people with the disorder. Compared to people with insomnia, people with bipolar disorder have better overall sleep efficacy.

March 2019

Last updated at: 5:18 am, 30th March 2019
To view documentation related to this topic download the files below
Fact Sheet Technical Commentary

NeuRA Libraries

Title Colour Legend:
Green - Topic summary is available.
Orange - Topic summary is being compiled.
Red - Topic summary has no current systematic review available.