context: Sleep researchers conclude that, in most cases, sleep paralysis is simply a sign that your body is not moving smoothly through the stages of sleep. Rarely is sleep paralysis linked to deep underlying psychiatric problems. var s_context; s_context= s_context || {}; s_context['wb.modimp'] = 'vidfloat'; if(webmd.useragent && webmd.useragent.ua.type === 'desktop'){ webmd.ads2.disable Initial Load(); webmd.ads2.disable Ads Init = true; $(function() { webmd.p.pim.increment(); $('.responsive-video-container').insert After('.module-social-share-container'); require(['video2/1/responsive-player/video-loader'], function(video Loader) { video Loader.init({ autoplay: webmd.useragent.ua.type === 'desktop' && ! !s_sensitive, chron ID: $('article embeded_module[type=video][align=top]:eq(0)').attr('chronic_id'), continuous Play: true, cp Options: { flyout: true }, display Ads: true, mode: 'in-article', sticky: true }) }); }); } else { $(function(){ $('.responsive-video-container').remove(); }); } Over the centuries, symptoms of sleep paralysis have been described in many ways and often attributed to an "evil" presence: unseen night demons in ancient times, the old hag in Shakespeare's Romeo and Juliet, and alien abductors. Almost every culture throughout history has had stories of shadowy evil creatures that terrify helpless humans at night. People have long sought explanations for this mysterious sleep-time paralysis and the accompanying feelings of terror. Sleep paralysis is a feeling of being conscious but unable to move. It occurs when a person passes between stages of wakefulness and sleep. During these transitions, you may be unable to move or speak for a few seconds up to a few minutes. Some people may also feel pressure or a sense of choking. Sleep paralysis may accompany other sleep disorders such as narcolepsy. Narcolepsy is an overpowering need to sleep caused by a problem with the brain's ability to regulate sleep. Sleep paralysis usually occurs at one of two times. If it occurs while you are falling asleep, it's called hypnagogic or predormital sleep paralysis. If it happens as you are waking up, it's called hypnopompic or postdormital sleep paralysis. As you fall asleep, your body slowly relaxes. Usually you become less aware, so you do not notice the change. However, if you remain or become aware while falling asleep, you may notice that you cannot move or speak. During sleep, your body alternates between REM (rapid eye movement) and NREM (non-rapid eye movement) sleep. One cycle of REM and NREM sleep lasts about 90 minutes. NREM sleep occurs first and takes up to 75% of your overall sleep time. During NREM sleep, your body relaxes and restores itself. At the end of NREM, your sleep shifts to REM. Your eyes move quickly and dreams occur, but the rest of your body remains very relaxed. Your muscles are "turned off" during REM sleep. If you become aware before the REM cycle has finished, you may notice that you cannot move or speak. Up to as many as four out of every 10 people may have sleep paralysis. This common condition is often first noticed in the teen years. But men and women of any age can have it. Sleep paralysis may run in families. Other factors that may be linked to sleep paralysis include: Lack of sleep Sleep schedule that changes Mental conditions such as stress or bipolar disorder Sleeping on the back Other sleep problems such as narcolepsy or nighttime leg cramps Use of certain medications, such as those for ADHD Substance abuse If you find yourself unable to move or speak for a few seconds or minutes when falling asleep or waking up, then it is likely you have isolated recurrent sleep paralysis. Often there is no need to treat this condition. Check with your doctor if you have any of these concerns: You feel anxious about your symptoms Your symptoms leave you very tired during the day Your symptoms keep you up during the night Your doctor may want to gather more information about your sleep health by doing any of the following: Ask you to describe your symptoms and keep a sleep diary for a few weeks Discuss your health history, including any known sleep disorders or any family history of sleep disorders Refer you to a sleep specialist for further evaluation Conduct overnight sleep studies or daytime nap studies to make sure you do not have another sleep disorder Most people need no treatment for sleep paralysis. Treating any underlying conditions such as narcolepsy may help if you are anxious or unable to sleep well. These treatments may include the following: Improving sleep habits -- such as making sure you get six to eight hours of sleep each night Using antidepressant medication if it is prescribed to help regulate sleep cycles Treating any mental health problems that may contribute to sleep paralysis Treating any other sleep disorders, such as narcolepsy or leg cramps There's no need to fear nighttime demons or alien abductors. If you have occasional sleep paralysis, you can take steps at home to control this disorder. Start by making sure you get enough sleep. Do what you can to relieve stress in your life -- especially just before bedtime. Try new sleeping positions if you sleep on your back. And be sure to see your doctor if sleep paralysis routinely prevents you from getting a good night's sleep.