This article was first published on March 7, 2023. It was last reviewed/ updated on March 8, 2023.
The term sleep paralysis is used to describe the experience of not being able to speak or move that typically occurs during the process of waking up but can also occur while falling asleep.
Usually, the experience is brief—typically lasting for only a few seconds.
Sleep paralysis usually ends on its own but it can also be ended by touching or speaking to the person, or by the person making intense efforts to move (American Academy of Sleep Medicine, 2014).
Sleep paralysis is often accompanied by hypnopompic hallucinations, but these are not always present along with sleep paralysis.
In one study of isolated sleep paralysis, nearly 60% of the subjects reported sensing a presence in the room with them during the sleep paralysis, and, of those, the majority believed it to be a non-human presence (Sharpless and Kliková, 2019).
What’s going on?
Essentially, the person is waking up in REM sleep and, so, cannot move (“atonia”). What is abnormal is that instead of REM activity and atonia happening while the person is asleep, they continue even as the person wakes up.
How common is it?
Occasional episodes of sleep paralysis (not amounting to a clinical diagnosis) are very common, especially in those under stress and who are sleep-deprived (Bentham, 2022).
A large population study in the United States found that 10 to 15% of the population reported having had at least one episode of sleep paralysis in the preceding year (Ohayon and Pakpour, 2022). It typically starts during adolescence.
In terms of lifetime prevalence, a review of studies reported that approximately 8% of the general population, 28% of students, and 32% of psychiatric patients experienced at least one episode of sleep paralysis in their lifetime.
But sleep paralysis may sometimes be due to an important underlying condition, as is discussed below.
Why is it important for us to look out for sleep paralysis?
1. As you can imagine, even though sleep paralysis is often “normal”, it can be quite anxiety-provoking for the person, especially when they have it for the first time (Scammell, 2003).
2. Sleep paralysis is more likely to occur in persons with psychiatric disorders including those who suffer from any of the following (Ohayon and Pakpour, 2022):
– Major depressive disorder
– Post-traumatic stress disorder
– Sleep deprivation due to any reason.
3. We should know that, according to their Prescribing Information, sleep paralysis can also be a side effect of any of the 3 dual orexin receptor antagonists (DORAs)—daridorexant, lemborexant, or suvorexant. If we can identify that the DORA is the cause, we can switch to a different sleep medication.
4. Sleep paralysis may occur by itself, a condition called recurrent isolated sleep paralysis, which is in the category of REM-sleep parasomnias in the International Classification of Sleep Disorders, 3rd Edition (American Academy of Sleep Medicine, 2014).
5. Most importantly, if we identify sleep paralysis in one of our patients, we must ask more questions to see if the person may have narcolepsy. It is one of the 4 classic clinical features of narcolepsy. We should make sure that we don’t forget these 4, which are:
– Excessive daytime sleepiness
– Sleep paralysis
– Hypnogogic/ hypnopompic hallucinations.
Note: Even though sleep paralysis is one of the 4 classic clinical features of narcolepsy, it is present in only about 25% to 50% of persons with this disease.
There is typically a delay of several years in the diagnosis of narcolepsy (Frauscher et al., 2013). We can help by identifying any of these 4 classic clinical features of narcolepsy that may be present in our patients and, if any one of them is present, asking about the other three.
How are hypnagogic/ hypnogogic “hallucinations” different?
What causes should we consider for hypnagogic/ hypnogogic “hallucinations”?
What is sleep paralysis and why is it important?
Potential side effects of dual orexin receptor antagonists (DORAs)
American Academy of Sleep Medicine. International classification of sleep disorders, 3rd ed. Darien, IL: American Academy of Sleep Medicine, 2014.
Benham G. Sleep paralysis in college students. J Am Coll Health. 2022 Jul;70(5):1286-1291. doi: 10.1080/07448481.2020.1799807. Epub 2020 Aug 19. PMID: 32813623.
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Frauscher B, Ehrmann L, Mitterling T, Gabelia D, Gschliesser V, Brandauer E, Poewe W, Högl B. Delayed diagnosis, range of severity, and multiple sleep comorbidities: a clinical and polysomnographic analysis of 100 patients of the innsbruck narcolepsy cohort. J Clin Sleep Med. 2013 Aug 15;9(8):805-12. doi: 10.5664/jcsm.2926. PMID: 23946711; PMCID: PMC3716672.
Ohayon MM, Pakpour AH. Prevalence, incidence, evolution and associated factors of sleep paralysis in a longitudinal study of the US general population. Sleep Med. 2022 Oct;98:62-67. doi: 10.1016/j.sleep.2022.06.003. Epub 2022 Jun 11. PMID: 35785587.
Scammell TE. The neurobiology, diagnosis, and treatment of narcolepsy. Ann Neurol. 2003 Feb;53(2):154-66. doi: 10.1002/ana.10444. PMID: 12557281.
Sharpless BA. A clinician’s guide to recurrent isolated sleep paralysis. Neuropsychiatr Dis Treat. 2016 Jul 19;12:1761-7. doi: 10.2147/NDT.S100307. PMID: 27486325; PMCID: PMC4958367.
Sharpless BA, Barber JP. Lifetime prevalence rates of sleep paralysis: a systematic review. Sleep Med Rev. 2011 Oct;15(5):311-5. doi: 10.1016/j.smrv.2011.01.007. Epub 2011 May 14. PMID: 21571556; PMCID: PMC3156892.
Sharpless BA, Kliková M. Clinical features of isolated sleep paralysis. Sleep Med. 2019 Jun;58:102-106. doi: 10.1016/j.sleep.2019.03.007. Epub 2019 Mar 23. PMID: 31141762.
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