Sleep paralysis

From The Book of THoTH (Leaves of Wisdom)

Sleep paralysis is a condition characterized by temporary paralysis of the body shortly after waking up (known as hypnopompic paralysis) or, less often, shortly before falling asleep (known as hypnagogic paralysis).

Physiologically, it is closely related to the normal paralysis that occurs during REM (rapid eye movement) sleep, also known as REM atonia. Sleep paralysis occurs when the brain is awakened from an REM state into essentially a normal fully awake state, but the bodily paralysis is still occurring. This causes the person to be fully aware, but unable to move. In addition, this state is usually accompanied by hypnagogic hallucinations.

More often than not, sleep paralysis is believed by the person affected by it to be no more than a dream. This is the reason why there are many dream recountings which describe the person lying frozen and unable to move. The hallucinatory element to sleep paralysis makes it even more likely that someone will interpret the experience as simply a dream, as one might see completely fanciful objects in a room alongside the normal vision one can see.