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Can Sleep Deprivation Cause Hallucinations

Seeing Things May Occur with Extreme Sleep Loss


Updated May 16, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Girl with sleep apnea/insomnia
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If you have ever experienced extreme sleep deprivation, you may begin to question your sanity, especially if you start to see things that are not there. You may even wonder: Can sleep deprivation cause hallucinations?

There are many reasons that people get inadequate sleep and become sleep deprived, from the demands of work and even home life to sleep problems like insomnia. Depending on the degree of sleep deprivation -- both how little we sleep and for how long we are sleep deprived -- there can begin to be important consequences to our health and well-being.

Beginning to hallucinate is among the more common symptoms of sleep deprivation. A hallucination is the perception of something that is not really present in the environment, as opposed to an illusion, which is the misinterpretation of something that is present. For example, seeing a cat where there is nothing is a hallucination, but mistaking your coat rack for a person is an illusion.

Depending on the length of sleep deprivation, approximately 80% of normal people in the population will eventually have hallucinations. Most of these are visual hallucinations. In contrast, people with schizophrenia often have auditory hallucinations, hearing things that are not there.

Sleep deprivation can actually cause other symptoms that mimic mental illness, such as disorientation and paranoid thoughts. In fact, one study found that 2% of 350 people who were sleep deprived for 112 hours experienced temporary conditions that were similar to acute paranoid schizophrenia.

Fortunately, these symptoms resolve when adequate sleep is obtained. So if you see something that isn’t there during a period of sleep deprivation, it might be time to get some rest.


Kryger, MH et al. "Principles and Practice of Sleep Medicine." Elsevier, 5th edition, pp. 502-503.

Mullaney, DJ et al. "Sleep loss and nap effects on sustained continuous performance." Psychophysiol 1983;20:643-651.

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