Sleep Paralysis

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 paralysis that occurs as a natural part of REM (rapid eye movement) sleep, which is known as REM atonia. Sleep paralysis occurs when the brain awakes from a REM state, but the bodily paralysis persists. This leaves the person fully aware, but unable to move. In addition, the state may be 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 explains 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 a dream, since completely fanciful, or dream-like, objects may appear in the room alongside one's normal vision.

Sleep paralysis occurs during REM sleep, thus preventing the body from manifesting movements made in the subject's dreams. Very little is known about the physiology of sleep paralysis. However, some have suggested that it may be linked to post-synaptic inhibition of motor neurons in the pons region of the brain. In particular, low levels of melatonin may stop the depolarization current in the nerves, which prevents the stimulation of the muscles, to prevent the body from enacting the dreamt activity.

Several studies have concluded that many or most people will experience sleep paralysis at least once or twice in their lives. Many people who commonly enter sleep paralysis also suffer from narcolepsy. In African-Americans, panic disorder co-occurs with sleep paralysis more frequently than in Caucasians. Some reports read that various factors increase the likelihood of both paralysis and hallucinations. These include:

Sleeping in an upwards supine position Irregular sleeping schedules; naps, sleeping in, sleep deprivation Increased stress Sudden environmental/lifestyle changes.

A lucid dream that immediately precedes the episode.

Also conscious induction of sleep paralysis is a common technique to enter a state of lucid dreams, also known as WILD.

Artificial sleeping aids, ADD medications and/or antihistamines Recent use of hallucinogenic drugs