What is Sleep Paralysis?
Sleep paralysis is a condition in which a person experiences a brief period, typically as they are waking up or falling asleep, during which they are unable to move. The episodes can last anywhere from a few seconds to a few minutes, during which the person may experience dream-like hallucinations or feelings of fear or dread.
During the sleep phase known as rapid eye movement (REM) sleep, the brain normally shuts down the nerves that control most muscle movement, effectively paralyzing your body, so you don’t act out your dreams. In the case of sleep paralysis, the inability to move continues as a person becomes partially conscious, resulting in a mixed state with features of both sleep and wakefulness. During the episode, the person typically can’t move, speak, or open their eyes. In addition, they often experience dream-like imagery and hallucinations, although they feel awake and aware of the paralysis and imagery.
Sleep paralysis is common, with an estimated 8% of people experiencing it at least once in their lives. The episodes may be associated with feelings of fear or anxiety, but they are generally not harmful, nor are they usually an indicator of any other disorder. However, recurrent sleep paralysis episodes may be a symptom of the sleep disorder narcolepsy.
Symptoms of Sleep Paralysis
Common symptoms of sleep paralysis include:
- Inability to move or speak despite feeling awake
- Hallucinations that may involve the perception of an intruder or dangerous presence
- Feeling that something is compressing your chest or suffocating you
- Feelings of fear, panic, dread, or anxiety
What Causes Sleep Paralysis?
Scientists don’t know precisely what causes sleep paralysis. The underlying cause is likely a problem with neurotransmitters, biochemicals that allow the brain to send signals to the muscles via nerve cells. These neurotransmitters normally work to inhibit movement during sleep so that, among other things, you don’t physically act out your dreams. In the case of sleep paralysis, the normal process of moving from sleep to wakefulness appears to be disrupted. During an episode, part of the brain becomes conscious and alert while the brain areas responsible for muscle movement are still inhibited. However, scientists don’t yet know what causes the disruption.
Some factors appear to increase the risk of sleep paralysis, including:
- Insomnia, sleep deprivation, or sleep disruptions
- Other sleep disorders
- Anxiety disorders
- Post-traumatic stress disorder (PTSD)
- Sleep apnea
- Family history of sleep paralysis or sleep disorders
Is Sleep Paralysis Hereditary?
Most of the time, sleep paralysis is caused by external factors, medical disorders, or other underlying conditions other than genetics. However, some research has suggested that people with a family history of sleep paralysis are more likely to experience the condition themselves. This suggests that a genetic component plays at least some role in the condition.
Researchers have not identified any specific gene or genetic mutation associated with sleep paralysis.
How Is Sleep Paralysis Detected?
Sleep paralysis is harmless for most people, but episodes that cause you anxiety, leave you feeling tired and unwell during the day, or occur frequently could be a reason to consult a doctor. Sleep paralysis that lasts for a long time and does not respond to lifestyle changes can be a cause for concern.
How Is Sleep Paralysis Diagnosed?
Doctors may take several different diagnostic steps when a patient is experiencing recurrent sleep paralysis:
- Physical and neurological exams. These basic exams will screen for indications of medical conditions that could be causing the sleep problems.
- Sleep history questionnaires. These questionnaires will ask the patient about their sleep habits and the degree of sleepiness they feel in different situations.
- Sleep logging. The specialist will likely want to monitor the patient’s sleep for a while. Sleep patterns may either be manually recorded by the patient or recorded electronically by a device that can detect periods of sleep and wakefulness. This step aims to find any association between the patient’s sleep routines and their sleepiness.
- Polysomnogram. This test involves monitoring the patient’s brain activity, heart rate, muscle activity, and eye movement as they sleep. The test is conducted during an overnight stay at a medical sleep center. The test can detect abnormal patterns of REM sleep characteristic of narcolepsy, and it may detect other sleep disorders that could be causing the symptoms.
- Multiple Sleep Latency Test (MSLT). During this test, the patient is monitored over a series of short naps spaced about two hours apart. This test aims to detect any unusual periods of REM sleep that occur during the short naps.
PLEASE CONSULT A PHYSICIAN FOR MORE INFORMATION.
How Is Sleep Paralysis Treated?
Most cases of sleep paralysis do not require treatment. Instead, doctors rely on patient education to assure the person that sleep paralysis is a common and typically harmless experience. Often, this reassurance is sufficient to relieve anxiety surrounding the episodes.
When sleep paralysis is causing significant distress, doctors may recommend psychotherapy, especially if PTSD, anxiety disorders, or other mental health-related issues seem to be triggering the sleep paralysis episodes.
Sleep paralysis associated with narcolepsy may be treated with medications, including:
- Stimulants. Modafinil and armodafinil are relatively new stimulants that help narcolepsy patients stay awake. These medications are less prone to side effects and addiction than older stimulants such as methylphenidate (Ritalin) and amphetamine, but these older medications may still be used in some cases.
- Sodium oxybate. The FDA has approved this drug to treat both sleepiness and cataplexy in patients with narcolepsy. However, it must be used with care because it can have life-threatening side effects when combined with sleep aids, narcotic pain relievers, or depressants such as alcohol.
- Antidepressants. Selective serotonin reuptake inhibitors (SSRIs) and norepinephrine reuptake inhibitors (SNRIs) such as fluoxetine and venlafaxine can help reduce narcolepsy’s REM-related symptoms.
How Does Sleep Paralysis Progress?
Sleep paralysis usually doesn’t cause long-term complications. For most people, the episodes are infrequent or may happen only once. However, about 10% of people who experience recurrent sleep paralysis feel significant distress associated with the episodes. As a result, they may be reluctant to sleep, leading to sleep disruptions or sleep deprivation. The loss of adequate sleep can itself lead to serious complications, including:
- Problems at work or school
- Relationship difficulties
- Accidents caused by fatigue or mental fogginess
- Anxiety or depression
- Substance abuse
- Weight gain
- High blood pressure
- Heart disease
How Is Sleep Paralysis Prevented?
There is no known way to prevent sleep paralysis. Doctors generally encourage good sleep habits and a healthy lifestyle to lessen sleep paralysis risk. Steps you can take to ensure better sleep include:
- Stick to a regular sleep schedule (even on weekends)
- Don’t eat or drink close to bedtime
- Avoid stimulating activities (e.g., watching TV, using electronics) 30 minutes before bedtime
- Use your bedroom only for sleep
- Keep your bedroom dark and cool
- Get plenty of exercise
- Limit consumption of caffeine and alcohol
- Quit smoking
- Try meditation or relaxation techniques
Sleep Paralysis Caregiver Tips
Some people with sleep paralysis also suffer from other brain and mental health-related issues, a condition called co-morbidity. Here are a few of the disorders commonly associated with sleep paralysis:
Sleep Paralysis Brain Science
Scientists are not sure what causes sleep paralysis, but it is likely the result of a problem related to brain chemicals called neurotransmitters. Neurotransmitters allow nerve cells to send signals to each other. Some of them increase cell-to-cell signals, allowing, for example, a signal for muscle movement to travel from the brain to the muscle cells, causing the muscles to move. Other neurotransmitters inhibit signaling, preventing unwanted or unnecessary signals from traveling from cell to cell.
During REM sleep, a part of the brain called the ventromedial medulla, and the spinal cord increase their output of inhibitory neurotransmitters. The resulting high level of these chemicals prevents nerve-cell signaling and effectively paralyzes the skeletal muscles, creating a state called atonia.
Sleep paralysis is likely caused by a disruption in this process, creating an imbalance of inhibitory and excitatory neurotransmitters. However, scientists are not sure what part of the brain the imbalance originates from or precisely which neurotransmitters are involved.
The episodes probably result from a mixed state in which part of the brain is asleep, and another part is awake. In the case of sleep paralysis, the parts of the brain that control movement and dream imagery remain in a sleeping state, while the parts responsible for conscious thought are awake.
Sleep Paralysis Research
Title: A Web-based Observational Study of Patient-reported Outcomes in Adults With Narcolepsy
Principal investigator: JeanPierre Coaquira, MPH
Palo Alto, CA
Nexus is a collaboration between academic institutions, advocacy, and industry to answer important questions about narcolepsy. It is a web-based observational study of patient-reported outcomes in adult patients with narcolepsy, with follow-up every six months.
Title: Awareness and Self-Compassion Enhancing Narcolepsy Treatment (ASCENT)
Contact: Jason Ong, PhD
Center for Circadian and Sleep Medicine, Northwestern University
This research aims to test the effectiveness of a mindfulness-based intervention (MBI) for improving health-related quality of life as a complementary practice to standard care for narcolepsy. This study is a feasibility trial in which 60 adults with narcolepsy will be randomized to receive either a 4-week (brief), 8-week (standard), or 12-week (extended) MBI. Each MBI will be delivered in small groups using a live videoconferencing platform and teaches mindfulness practices to help cope with narcolepsy symptoms. By developing a scalable mind-body intervention, this project can address a major research gap on improving psychosocial functioning in people with narcolepsy.
Title: Modafinil Versus Amphetamines for the Treatment of Narcolepsy Type 2 and Idiopathic Hypersomnia
Principal investigator: Lynn Marie Trotti, MD
Emory Sleep Center
For diseases that cause excessive daytime sleepiness (such as narcolepsy and idiopathic hypersomnia), several medications can be used to treat sleepiness. However, it can be difficult to decide which medication to use for a particular individual for several reasons: 1) there are very few studies that directly compare two medications to see which works best; 2) there are very few studies that include people with a disorder of sleepiness called idiopathic hypersomnia.
To address this gap in knowledge, the researchers propose a randomized clinical trial comparing modafinil and amphetamine salts in patients with narcolepsy type 2 or idiopathic hypersomnia. All participants will either receive modafinil or amphetamine salts — no participant will receive a placebo.
This study will evaluate which medication works better to improve sleepiness. The researchers will also see which medication is better for other symptoms including difficulty waking up and difficulty thinking, as well as seeing which medication causes fewer side. Finally, this study will see if any information about patients (such as age or sleep study features) predicts responding better to one medication or the other.