Sleep paralysis is a condition characterized by brief periods of paralysis as the patient falls to sleep or wakes up. It is usually associated with other sleep disorders, rather than appearing on its own, and since it is often accompanied by hallucinations, it can sometimes be very frightening for patients. People often feel what they describe as a presence in the room when they experience the condition, and many cultures have complex folklore surrounding it.
This disorder is especially common in people who experience narcolepsy, but it is also associated with lack of sleep, poor sleeping conditions, stress, and other sleep problems. On its own, the paralysis is not inherently harmful, although it can be scary, and it can also be a sign of a more serious problem that needs to be addressed. Repeated episodes, especially if accompanied by terrifying hallucinations, should be reported to a medical professional.
When someone experiences sleep paralysis, the body feels heavy and immovable, and the patient may feel like he or she cannot speak. The condition is actually very similar to REM atonia, a natural form of paralysis that sets in during the deep stages of REM sleep to keep the body from acting out the movements experienced in dreams. This condition, however, occurs at the edges of REM sleep, rather than in the most intense part.
Paralysis episodes can last a few seconds to several minutes. Sometimes, external stimuli, such as a voice or touch, can pull someone out of it, and in other cases, the patient may be unreachable. Sleep paralysis occurs most often when people sleep on their backs and, in some cultures, it is known as the “Old Hag,” in reference to the idea that it is caused by an old hag sitting on the patient's chest.
Some people have suggested that this disorder might be the rational explanation behind myths of alien abductions, succubi, vampires, and other malevolent nighttime visitors. Since the hallucinations associated with this problem can be extremely vivid and often very strange, people with active imaginations might have had trouble understanding that the events “experienced” did not actually happen.
Sometimes, sleep paralysis can be addressed with the use of prescription drugs. It can also be beneficial to make adjustments to a sleep routine and to probe into the root causes of the problem to see if those can be treated to eliminate the issue. Other people take a different approach, using psychology in an attempt to control the hallucinations, turning the paralysis into an interesting, rather than frightening, experience.