Home HealthTopics Health Centers Reference Library Research
Join us on Facebook Join us on Facebook Share on Facebook

Sleep Disorders




Can lack of sleep cause hallucinations? I know someone who had not slept for 4 straight nights and experienced this. Thanks.


The short answer to your question is yes, acute sleep deprivation can result in hallucinations! Many if not most individuals will experience some problems with distortions of reality and even hallucinations if they undergo sleep deprivation for a long enough time period. The likelihood of this happening in any given individual will depend on the nature and duration of the sleep deprivation as well as certain individual factors (such as age, physical condition, etc.).

Aside from effects on mental function, acute sleep deprivation can have other effects that may range from changes in hormone levels to alterations in the immune system function (ability to fight infection). Fortunately, most of these changes reverse with recovery sleep and there are no permanent effects of acute sleep deprivation that are known at this time. However, severe acute sleep deprivation, such as you mention in your question, is not recommended.

Aside from acute sleep deprivation, there is an association with sleep and hallucinations in a condition called hypnogogic or hypnopompic hallucinations. This is a scenario where as one falls asleep or as one is waking up, the individual sees or hears things that are not physically present (i.e. hallucinates). It is as if they are having vivid dreams as they are waking up or falling asleep. This type of symptom can be seen in the absence of sleep deprivation and is most commonly linked to narcolepsy, though can occur in individuals without narcolepsy as well.

It’s important to recognize that hallucinations can occur for reasons other than sleep deprivation and sleep-related disorders, such as in certain psychiatric conditions (i.e. paranoid schizophrenia) and side effects from some medications. It’s important to place the hallucinations in the context of the individual case. If your friend has ongoing problems with hallucinations, then further evaluation should be considered. Talking to his or her primary care physician would be a good place to start.

If you have other specific questions about sleep, lack of sleep, or other sleep disorders, please visit the American Academy of Sleep Medicine website. In addition to information, the website contains a list of Sleep Centers and Sleep Specialists across the country so that you may locate one near you.

For more information:

Go to the Sleep Disorders health topic, where you can:

Response by:

Meena S Khan, MD Meena S Khan, MD
Clinical Assistant Professor of Pulmonary, Allergy, Critical Care & Sleep
Clinical Assistant Professor of Neurology
College of Medicine
The Ohio State University