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Sleep Paralysis

Saba Ashraf's picture


The Phenomenon of Sleep Paralysis

            For the past couple of years, I have experienced sleep paralysis every few months, particularly after midnight and before 3 am.   This sleep paralysis I mentioned corresponds to an inability to carry out voluntary muscle movements during sleep onset (hypnogogic or predormital form) or waking up (hypnopompic or postformtal form) (4). Basically, I would wake up in the middle of the night and would be completely unable to move for a couple of seconds, until I relaxed. At first, I didn’t think much of the sleep paralysis I felt because it was so minor, but I started to get more interested in learning about sleep paralysis when I realized others were also experiencing the same phenomenon in more unique ways. For instance, some individuals who have experienced sleep paralysis have stated that they felt a ghostly presence in the room or had the feeling that someone was choking them at the time. Although certain individuals who have had sleep paralysis episodes believe it was caused by supernatural events, there are also scientific reasons that cause sleep paralysis.

Sleep paralysis is thought to be related to narcolepsy, which is a neurological sleep disorder that causes individuals to have excessive sleepiness during the day that results in uncontrollable naps (4). Many individuals that have narcolepsy will experience episodes of sleep paralysis. However, one does not need to have this sleep disorder to experience sleep paralysis (4).   Symptoms of sleep paralysis include an inability to move the limbs, partial or complete skeletal muscle paralysis, and visual/auditory hallucinations, which are rare (4). These hallucinations can occur during sleep onset or awakening from sleep and are responsible for the feeling of having someone else in the room or the sensation of another being sitting on one’s chest during an episode of sleep paralysis (2). All of these symptoms last from about a few seconds to 1 or 2 minutes (2). The symptoms associated with sleep paralysis can disappear if the person experiencing sleep paralysis is physically touched or moved by another person (2). Through my own experiences, I have also noticed that relaxing one’s mind during sleep paralysis, rather than panicking, will make the symptoms disappear quicker as well. Also, sleeping on one’s back will increase the chance that someone will get an episode of sleep paralysis. However, I have realized that there is no guarantee that individuals will be on their side/stomach the whole time they are sleeping because movement is common during sleep.  

            Also, certain factors that can result in sleep paralysis include stress, sleep deprivation, and a genetic factor, which is very uncommon (5). About 20-60% of people have experienced sleep paralysis once, depending on the group of people under study (3). Sleep paralysis is most commonly found in adolescents. In fact, about 21% of undergraduate college students have had an episode of sleep paralysis, where as only 4% have experienced more than 5 episodes during their lifetime (3). I thought the 21% of undergraduate college students experiencing sleep paralysis was a relatively large percentage at first; however, this number makes sense considering the fact that some undergraduates don’t seem to get enough sleep many nights or have a regular sleeping schedule.

In order to understand sleep paralysis more closely, one must examine the normal sleeping stages that usually consist of five stages. Stage 1 consists of a light sleep in which the eyes wanders slowly, muscle activity decreases, and sudden muscle contractions can occur (6). In fact, this is the particular stage that individuals experience the sensation of falling. Stage 2 is made up of no eye movement, slower brain waves, and rare rapid brave waves (6). Stages 3 and 4 are commonly known as the deep sleep stages in which the brain creates delta waves and there is a lack of eye movement and muscle activity (6). Stages 1-4 are known as the NREM, or non- rapid eye movement periods. Lastly, the last stage is compromised of the REM period, or rapid eye movement period, that consists of rapid breathing, rapid eye movements, the temporary paralysis of the limbs, and dreaming (6). Increase in heart rate and blood pressure is also characteristic of the REM stage (6).

This REM phase is also related to sleep paralysis since individuals that go through a sleep paralysis episode will experience it in the REM stage of sleeping. One of the main characteristics of the REM stage, muscle atonia, is the temporary paralyzation of skeletal muscle (1). The muscle atonia prevents individuals from physically carrying out their dreams. For instance, when humans dream that they are running, they are unable to actually run in reality because of muscle atonia. The neural structures responsible for muscle atonia are located in the dorsolateral portions of the pons located in the brainstem (1). During REM sleep, neural activities generating muscle atonia descend through the medulla and spinal cord, and inhibit the motorneurons in the brainstem and spinal cord (1). Sleep paralysis is actually a type of REM dysregulation. In fact, the cause of sleep paralysis is “a marked dissociation between level of alertness and muscle atonia that often occurs in SOREM (sleep onset –REM) sleep episodes (1).” Individuals who experience SOREM sleep episodes are intentionally awakened during their sleep (3). People may see hallucinations of their dream during sleep paralysis due to the fact they are in the REM phase (when dreams take place) and sleep paralysis blurs the line between sleeping and being awake (5). In order to prevent further episodes of sleep paralysis, certain measures can be taken. These include getting enough sleep, reducing stress, exercising regularly, and keeping a regular sleep schedule (4).

Now that the scientific reasons for sleep paralysis have looked at, certain individuals also believe that sleep paralysis is caused by supernatural occurrences. Three types of ghostly attacks are thought to take place during sleep paralysis. These include pressing the body of the person, tying the body of the person, and controlling the mind, body, and intellect of the person (5). Believers that are certain sleep paralysis is caused by supernatural forces are convinced that the hallucinations that they see during episodes of sleep paralysis are not hallucinations, but actual ghosts that are attacking them. What was even more amusing was that sleep paralysis is thought to occur more in young adults because worldly desires tend to be at their highest during adolescence, so adolescents become targets for ghosts to possess them (5). Those who believe a ghost was attacking them assume that the ghost is seeking revenge, trying to satisfy their desires, trying to gain pleasure by troubling others, and tormenting the seekers of God (5). In order to prevent further attacks, individuals are told to begin spiritual practice, praying, chanting the name of God, and taking part in spiritual healing remedies (5). 

Knowing that there is a scientific reason for sleep paralysis definitely calms the minds of many, including my own, that have frightening or minor episodes of sleep paralysis. After all, it is much more comforting knowing you are being disturbed during your REM sleep than having a ghost attack you in the middle of the night.   Personally, it was also helpful to see the different causes of sleep paralysis, especially since I have experienced this phenomenon and noticed that I am sleep deprived or lack a regular sleeping schedule when I experience an episode of sleep paralysis. Learning about sleep paralysis disorder brought a new understanding of this phenomenon to me because even though I experienced it, it was very minor and many others were experiencing a version of sleep paralysis I hadn’t known. It will be particularly interesting to see what researchers will find out about sleep paralysis in the future, since research on sleep paralysis has only been recent. I also wonder if an increase in scientific research about sleep paralysis will have an affect on those who believe sleep paralysis is a supernatural experience.    


Works Cited


1) Hishikawa, Y. Shimizu, T. “Physiology of REM sleep, cataplexy, and sleep

paralysis.” NCBI. 03 April 2010. <>


2) “Isolated sleep paralysis.” NLM. 12 June 2009. 03 April 2010. 



 3) McCarty, David E. Chesson, Andrew L. “A Case of Sleep Paralysis with

Hypnopompic Hallucinations.” NCBI. 15 Feb. 2009. 03 April 2010.



4) “Sleep Paralysis.” Stanford. 26 Jan 1999. 03 April 2010. 



 5) “Spiritual research into Sleep Paralysis.” Spiritual Research Foundation. 2010.

03 April 2010.



6) “Stages of Sleep.” Sleepdex. 03 April 2010.                                                                         <>



Paul Grobstein's picture

Sleep paralysis ... research and stories

"I also wonder if an increase in scientific research about sleep paralysis will have an affect on those who believe sleep paralysis is a supernatural experience."

An interesting question indeed.  For some extensive and significant observations on this subject, see on-line comments following Sleep paralysis: awake but still asleep.  Including one of my own