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I wrote the following article for Fortean Times, but it was never accepted for publication -- which is why it's ended up here. Other SP articles of mine will be added in due course.



 Assaulted by Spirits: Exploring the Mystery of Sleep Paralysis


© Louis Proud


Whenever I'm talking with a group of people about the topic of ghosts or spirits, more often than not someone relates a 'ghostly encounter' of their own -- an experience that occurred, not while they were awake, but while they were paralysed and half-asleep. They could sense, they claim, an evil presence in the room, forcing them down on the bed, trying to possess their mind and body. Perhaps they could feel it sitting on their chest, even whispering in their ear. After struggling for a moment, they managed to wake up completely. Never before had they felt so afraid.


Such 'ghostly encounters' are actually sleep paralysis (SP) episodes, and are much more common than one would think. Around 25-40% of those reading this article has had an SP experience in the past, or will have an SP experience at some point in their life. They usually occur subsequent to REM (rapid eye movement) sleep, the stage of sleep in which dreaming takes place. So as to prevent ourselves from enacting dream activity and causing injury -- like kicking our legs while dreaming about running -- the body becomes paralysed during REM sleep. In the case of a typical SP episode, one has emerged from REM sleep, yet bodily paralysis persists -- sometimes up to several minutes, though usually for a matter of seconds.


Of course, many SP episodes are interpreted as paranormal experiences, especially when accompanied by hypnagogic or hypnapompic hallucinations, which can be visual, tactile, or auditory. The hypnagogic state is the state of intermediate consciousness preceding sleep; the latter, following sleep. The two conditions are virtually identical, and the term hypnagogic is often used to cover both.


As they basically occur in a half-awake/half-asleep state, SP episodes are classified as hypnagogic experiences, but with the added ingredient of paralysis. Paranormal researchers have long identified the hypnagogic state as being extremely conducive to psi. Some shamans, apparently, can induce the state at will, such as by holding themselves on the edge of sleep, using it as a 'gateway' into the 'spirit world'.


In recent years, sceptics of the paranormal, such as Susan Blackmore, have had a lot of fun with the topic of SP, using it to dismiss almost every nocturnal paranormal phenomenon in existence, from alien abduction episodes to out-of-body experiences (OBEs). According to the official, scientific explanation, SP episodes are caused by abnormal brain activity and are dream-related and entirely hallucinatory.


Not all experts agree, however. The SP pioneer David J. Hufford, author of The Terror That Comes in the Night, notes that "the specific contents of the experience have not been explained...If they are related to ordinary dreams by the presence of REM physiology, why is their content so consistently the same without apparent regard for culture? Hufford is quoted as saying: "I don't have a good explanation for these experiences."


SP episodes can be so profound and powerful, so frightening and convincing, that one is left with the conviction that spirits and demons are real. For those who have episodes on a regular basis, a firm belief in the paranormal is common. I myself am a chronic SP sufferer, and have also written a book about the phenomenon -- titled Dark Intrusions: An Investigation into the Paranormal Nature of Sleep Paralysis Experiences -- so I can see why many subscribe to the 'discarnate entity theory', a theory I find quite appealing, and not at all ridiculous or irrational.


The SP phenomenon has had a significant impact on religion and mythology throughout the ages. In almost every culture throughout the world, one will find reference to SP and, indeed, the supernatural entities thought to be responsible for such terrifying encounters. In England, during the Middle Ages, to have a 'nightmare' was to have an SP experience -- an experience attributed to the influences of a 'mare', a demonic being thought to attack people in the night, causing a sensation of pressure on the chest. Nowadays defined as having a worn or gaunt appearance, through illness, lack of sleep, etc., the term 'haggard' also relates to SP, for it was once believed that witches or hags attacked men in the night by riding on their chests as they slept.


In Chinese folklore, SP experiences are believed to be a form of minor body possession, caused by the forces of the dead. The Chinese name for SP translates as 'ghost pressing on body', or 'ghost pressing on bed'. During sleep, believe the Eskimo people of Alaska, the soul leaves the body and goes wandering, leaving one vulnerable to the influence of spirits. When an SP attack occurs, they say, a spirit has tried to take possession of one's body and must be fought off. 


Without a doubt, the most compelling and frightening SP episodes are those that involve hallucinations, rather than just paralysis. Common to many experiences is the 'sensed presence', the feeling that one is accompanied by a presence, usually malevolent. One may feel as though the presence is watching one, or is trying to possess one's mind and body. In a paper written by Canadian Psychologist J. Allan Cheyne, titled The Ominous Numinous, one SP sufferer described the presence they sensed as "purest evil, out to possess my soul. The presence was ALWAYS evil, and I could always feel it trying to enter my body."


As for tactile hallucinations, one may feel the presence touch one's body, such as on the face, hands and shoulders. "Being grabbed by the hands and wrists is particularly common," explains Cheyne. Sometimes the bed is felt to sink down as the presence approaches, giving the impression of something solid. If the presence is particularly malevolent, one may even feel a pair of hands around one's neck. These sensations, though obviously not real in the physical sense, can nonetheless be very unpleasant.


Especially interesting are the auditory hallucinations of SP sufferers. Some of the sounds most often heard include buzzing, whistling, and ringing noises, footsteps, laughter, breathing, growling, and the sound of doors opening and closing. Voices are also heard. They can be far away or extremely close, internally heard or externally hears, indistinct and unintelligible, or clear and comprehensible. Generally, they are not taken to be self-generated. "The voices may simply call out the sleeper's name, but more often, they utter a threat, warning, command or a cry for help," explains Cheyne.


On the University of Waterloo's SP webpage, which is run by Cheyne, one woman reported the following experience: "As I listened I could sense this 'thing' walk or hover over my head, very close directly over my ear. It said 'Freya!' The voice continued: 'I've got work for you to do!' Then I listened as the presence hovered for a few seconds more and moved across the room to sit on my roommate's bed."


In sleep researcher Jorge Conesa Sevilla's Wrestling with Ghosts, a twenty-four year old SP sufferer reported hearing a male voice coming from the ceiling, which said: "It's time to play games now." This comment, like so many others SP voices, is creepy, cryptic, threatening and striking similar in tone to 'spirit voices' reported by witnesses in haunted locations.


As SP attacks can occur with the eyes open, one may perceive one's attacker while the experience is taking place. Often the entities seen have piercing black eyes and a dark, shadowy form. And, instead of being perceived directly, are located on the periphery of one's vision, or are obscured by shadows. In The Terror That Comes in the Night, one young man whom Hufford interviewed, a medical student named Jack, described seeing a seven foot tall caped and silhouetted figure with "very dark eyes." As he lay on his bed in a state of fear and paralysis, Jack couldn't help but stare at the figure. It had long brown hair, and appeared to be wearing some sort of hat.


A man in his early-twenties, named Ron, told Hufford of a terrifying encounter he had had with an evil "murky presence" with a "glaring stare to it." One afternoon while napping, Ron, a college student at the time, suddenly woke up to the sound of the door slamming. Although unable to move, Ron managed to open his eyes, and was able to see quite clearly. He noticed the door was still closed, and that his roommate had not entered the room as suspected. Ron felt a great pressure on his body, which gradually increased in intensity.


Suddenly he saw a "grayish, brownish murky presence" sweep towards him from a darkened area of the room, changing from a gaseous blob into a rectangular-shaped creature with sharp edges. It approached the bed, "and kind of stood over me with a glare." Ron could feel, emanating from the entity, a very definite feeling of menace. As the being began to "envelope the bed," the pressure was so intense that Ron felt as though he were being crushed to death. Before long, the experience "kind of dissipated away," and Ron woke up completely.


SP experiences like Ron's and Jack's are difficult to explain, as they do not resemble dreams in any shape or form. Why is it, one wonders, that the so called hallucinations of SP sufferers, removed by time and culture, are so remarkably similar? If these experiences were dream related, much the opposite would be true, as anything can happen in a dream. Which is not to imply that SP episodes and dreams should be placed in separate categories. In fact, recent research has revealed that although one feels awake and alert during the SP state, the brain nonetheless displays electrical activity typical of REM sleep, suggesting -- but not proving -- that SP experiences are an intrusion of REM activity into wakefulness.


Furthermore, the SP state and the dreaming state are not that far removed, with some SP suffers using the condition as a way to induce lucid dreams, even OBEs, the former and the latter sharing much in common. Apparently, when the SP state is accompanied by strong feelings of vibration, this marks the prelude to an OBE, enabling one to eject one's 'astral body' from one's physical body, and thus transform the experience into something pleasant and exciting. Sometimes, too, this alleged 'separation' can occur by mistake.


In response to an article of mine on SP, published in New Dawn in 2007, one woman, a chemistry and mathematics teacher, wrote to tell me of a series of SP experiences she'd had about twenty years ago, when she was a young mother, one of which involved an apparent OBE. I will call her Pam. "I had suffered from quite a few episodes of SP on waking up and I found them very irritating," she explains. "At first I would try desperately to move but I would inevitably have to wait until the episode passed and I fully woke up."


One afternoon, while taking a light nap, Pam 'half woke up' to the sound of her son crying in the next room. Her body was entirely paralyzed, though she was able to open her eyes. Desperate to wake up and go comfort her son, Pam tried desperately to move. The thought occurred to her that, if she could only make it over to the en suite opposite her bed, she would be able to throw some water on her face and wake up properly. Pam explains what happened next:


"I made an enormous effort, willing myself to move but popped out of my body and started travelling upwards instead of across the bed to the en suite...I recall there was a slight whooshing sound as I travelled upwards and out of my body. I quickly panicked as I thought I was dead. I started thinking that my son would be left crying in his bed and my husband would come home and find me dead. When I really panicked I returned to my body and instantly woke up."


Bearing in mind that the SP state is highly conducive to experiences like Pam's, and, moreover, that the phenomenon is associated with the hypnagogic state -- that 'portal' into the 'spirit world' -- it would seem that we're dealing with something genuinely paranormal -- something, perhaps, that allows one entry into another 'realm'. Or, put another way, alters one's perception in such a way that one is able to perceive normally invisible phenomena, like Jack seeing the hooded figure with dark eyes.


This article started with the topic of nocturnal ghostly encounters, and how many of them fail to be accurately identified as SP experiences. Whenever I hear such stories, of course, I always tell the narrator that what they underwent was most likely an SP episode, something benign and common. During one such conversation, with a man in his mid-twenties who claimed to have been "attacked by a spirit" one night, he looked me straight in the eyes and said: "It's all well and good to have a label for my experience, but how does it explain what occurred?" Like Hufford, I had no explanation to give him. For all I know, maybe he did encounter a spirit.





  • Cheyne, J. Allan., A Webpage About Sleep Paralysis and Associated Hypnopompic and Hypnagogic Experiences,


  • Cheyne, J. Allan, The Ominous Numinous: Sensed Presence and 'Other' Hallucinations, Journal of Consciousness Studies, 8, No. 5-7, 200


  • Hufford, David J., The Terror That Comes in the Night: An Experienced-Centered Study of Supernatural Assault Traditions, University of Pennsylvania Press, USA, 1982


  • Sevilla, Jorge Conesa, Ph.D., Wrestling With Ghosts: A Personal and Scientific Account of Sleep Paralysis, Xlibris Corporation, USA, 2004