You wake up. You're pinned to the bed.
You know you're awake but you can't move. You might see shadows moving towards you – you might even see demons or ghosts.
Sarah Kirk, 23, is a Christchurch woman who has experienced this terrifying and surprisingly common condition known as sleep paralysis.
"Sleep paralysis is the most frightening thing that has ever happened to me. When it happens to me I am completely paralysed but I know what's happening around me. There is always a person who I feel is coming to get me but it's not like in a dream where you are somewhere else," she said.
"I know I am in my room and lying in my bed but I can't do anything about it and it's like I'm hallucinating and it's like this ghost or shadow sweeps into my room, and I panic and am terrified and I feel like I am trapped in my own body but can't wake myself up or move."
Alex Bartle, director of the Sleep Well Clinic, said sleep paralysis was caused by people exiting rapid eye movement (REM) sleep, during which many muscles were paralysed.
"All our voluntary muscles – arms, legs – are paralysed but involuntary muscles like our heart keep on working. That means REM sleep intrudes into wakefulness, so if you don't immediately click out of REM sleep and wake up, then you may continue to have this paralysis."
Most of the REM sleep is in the latter part of the night and most patients suffer from the paralysis in the morning when they wake up, he said.
Narcolepsy, a condition in which people fell asleep at inappropriate times, also caused people to enter REM sleep quicker than normal and some sufferers then experienced paralysis early in the night, he said.
Sleep paralysis also occurred when people were excessively tired.
"People are still in dreamland [REM sleep] but they're actually waking up so they're actually caught halfway between wakefulness and dream sleep."
He only saw three or four sleep paralysis cases a year.
Christchurch woman Lynley Capon, 55, endured a decade of irregular sleep paralysis between the ages of 20 and 30.
"Usually it was before I went to sleep. I'd be drifting into sleep and then there would be a rushing sound in my ears and something really heavy pressing on my chest and I couldn't breathe very well.
"I'd have have this huge desire to call out to someone to help me but not be able to, or [to] move or anything. I was absolutely petrified as I didn't know what was happening. I thought it was something evil that was happening to me."
Lynley's daughter, Hannah Capon, 26, has also suffered from intermittent sleep paralysis in her 20s.
"The first time I woke up and I was in my bed and I was lying on my back and it was completely dark, the sheets were going really tight across my body and I thought they were going to crush me. That went on for probably only a couple of minutes but it was terrifying."
She has endured a number of other sleep paralysis experiences where she saw cats in the room even though there were none in the house.
A recent survey at Goldsmiths College in London found more than 50 per cent of the British population would experience sleep paralysis.
"It appears that up to 50 per cent of the population will experience sleep paralysis in one form or another at least once in their lifetime, and some people experience it far more often than that," the research paper said.
"It's easy to understand why reports of alien abductions are often associated with the phenomenon as attacks often involve feelings of intense fear, terror, bliss, joy, anger, and feelings of dying or imminent death."
The condition had many paranormal connotations in different cultures. In parts of the world it is called "the old hag" as people thought a hag was sitting on the victim while in the West Indies it is known as "kokma" describing a ghost baby who attacks the sleeper.
- © Fairfax NZ News
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