Sleep paralysis sounds unbelievable. You wake from sleep. As you lie in bed, you feel like someone is standing over you in the darkness. You try to move your head only slightly to take a subtle glance, but you can't. Someone -- something -- is surely holding you down. You attempt to struggle, to thrash your arms and legs, but you are frozen in place. Sheer panic washes over you as your paralysis lingers.
Though this may sound all too unreal, sleep paralysis is indeed a very real experience.
What Exactly Is Sleep Paralysis?
If you have experienced something similar while awakening, you are familiar with the unforgettable horrors of sleep paralysis. Sleep paralysis is a transient inability to move or speak as one goes from sleep to wakefulness, without other findings characteristic of narcolepsy. In sleep paralysis, this often occurs while awakening (hynopompic) as opposed to falling asleep (hypnagogic), which is more common in narcolepsy.
Features of Sleep Paralysis
There are some common features of sleep paralysis, including:
- Eye movements are typically preserved.
- It more often occurs while sleeping on one’s back.
- Visual and auditory hallucinations often occur and may include a sense of an evil presence, of being touched, or hearing voices or noises in the room.
- Occasionally faces or people may be seen at the bedside.
- A sense of breathlessness (or chest pressure, even someone standing on one’s chest) may exist.
How Often Does Sleep Paralysis Occur?
It is common and may be experienced by 20% to 60% of people, depending on the population examined. In a study of college students, 21% were found to have had at least one episode of sleep paralysis, but only 4% had 5 or more episodes. It is believed to be precipitated by sleep deprivation, stress, and sleep schedule disruption. In experiments, it has been shown to occur with disruption of rapid eye movement (REM), or dream sleep. It also is associated with anxiety disorders.
