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, sleep paralysis can sometimes be very frightening for patients. This condition is especially common in people who experience narcolepsy, but it is also associated with lack of sleep, poor sleeping conditions, stress, and other sleep disorders. On its own, sleep paralysis is not inherently harmful, although it can be scary, and it can also be a sign of a more serious problem which needs to be addressed. Repeated episodes of sleep paralysis, especially if accompanied by terrifying hallucinations, are definitely cause for a trip to the doctor.
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 which sets in during the deep stages of REM sleep to keep the body from acting out the movements experienced in dreams. Sleep paralysis, however, occurs at the edges of REM sleep, rather than in the most intense part.
Sleep paralysis episodes can last a few seconds to several minutes. Sometimes, external stimuli such as a voice or touch can pull someone out of sleep paralysis, and in other cases, the patient may be unreachable. Sleep paralysis occurs most often when people sleep on their backs.
To understand what causes sleep paralysis, it is helpful to know what normally happens when you are asleep.
Sleep happens in cycles, each of which is split into two phases: non-REM and REM sleep. REM stands for rapid eye movement, as the eyes dart around during this stage. The brain is very active in REM sleep and most dreams occur during this period. Also during this time, the body is paralysed, apart from the eyes and diaphragm (the main muscle used in breathing). It is thought that this occurs to stop us acting out the actions in our dreams. Sleep paralysis happens when the normal muscular paralysis of REM sleep temporarily continues after you have woken up.
Certain factors make you more likely to get sleep paralysis:
sleep deprivation – sleep paralysis is more common in people who do not get enough sleep
irregular sleeping patterns – people with irregular schedules or who do shift work are more prone to sleep paralysis
age – it is more common in teenagers and young adults
narcolepsy – some people who have narcolepsy, a sleep disorder, also experience sleep paralysis
genetic link – sleep paralysis may have a family link, although this theory needs more research
Sleep paralysis entails one or both of the following:
Paralysis: occurs after waking up or just before falling asleep. You cannot move any body part, aside from involuntary movements such as blinking and breathing. This paralysis is the same paralysis that occurs when dreaming. The brain paralyzes the muscles to prevent possible injury during dreams, as some body parts may move during dreaming. If the person wakes up suddenly, the brain may still think that it is dreaming, and sustains the paralysis.
Hallucinations: Images or sounds that appear during the episode. The sensation that someone is standing beside you or somewhere close by in the room. Strange sounds. Some people feel a heavy weight on their chest, as if they are being sat on.
There are several ways that sleep paralysis can be treated.
Sleep paralysis is more common in people who are sleep deprived, so getting enough sleep could reduce the number of episodes of sleep paralysis you have. Most adults need around six to nine hours of sleep each night.
Keeping a regular sleeping schedule, where you go to bed and get up at roughly the same time, can also help.
Tips for improving your sleeping habits include:
creating a restful sleeping environment that is quiet, dark and not too hot or cold
making sure your bed is comfortable
exercising regularly, but not close to bedtime
cutting down on caffeine
not eating or drinking alcohol before bedtime
not smoking, as nicotine is a stimulant
If your sleep paralysis is particularly troublesome, you may be prescribed a short course of medication called a tricyclic antidepressant, such as clomipramine. Antidepressants are most commonly used to treat depression, but they can also treat severe sleep paralysis.
The medication works by altering the depth of REM sleep. This should stop the temporary paralysis when you wake up or fall asleep, and should also reduce the number of any hallucinations you have. The medication may be taken for a month or two to see if it improves your symptoms.
Sometimes, sleep paralysis can be a symptom of the disorder narcolepsy, which causes sudden, unexpected "sleep attacks". Read about Narcolepsy Treatment for more information about treatments for this condition.