What Triggers Sleep Paralysis?

In sleep paralysis, a type of sleep disorder called a parasomnia, people experience a brief loss of muscle control (atonia) that occurs just after falling asleep or waking up. Hallucinations may also occur.

Sleep paralysis is a type of sleep disorder called a parasomnia, which is an abnormal behavior that occurs while sleeping. In sleep paralysis, people experience a brief loss of muscle control (atonia) that occurs just after falling asleep or waking up. Hallucinations may also occur.

Symptoms of sleep paralysis include:

• Inability to move the body shortly after falling asleep or waking up (atonia)
• During an episode of atonia, a person feels awake and is aware of the loss of muscle control
• Hallucinations that are different from typical dreams
• Intruder hallucinations: the perception of a dangerous person or presence in the room
• Chest pressure hallucinations (incubus hallucinations): a feeling of suffocation
• May occur along with intruder hallucinations
• Vestibular-motor (V-M) hallucinations: includes feelings of movement (such as flying) or out-of-body sensations
• Fear
• Distress

Episodes of sleep paralysis may last from a few seconds to up to 20 minutes, with an average time between six and seven minutes. 

The cause of sleep paralysis is unknown, but multiple factors are believed to trigger the condition:

• Other sleep disorders
  • Obstructive sleep apnea
  • Narcolepsy
  • Nighttime leg cramps
  • Insomnia
  • Excessive daytime sleepiness
  • Circadian rhythm disorders, in which the day-night cycle is not aligned, such as people with jet lag and shift workers
• Certain mental health conditions
  • Anxiety disorders, including panic disorder
  • Post-traumatic stress disorder (PTSD)
  • Bipolar disorder
  • Exposure to childhood sexual abuse or other types of physical and emotional distress
• Stopping alcohol or antidepressants
  • Can lead to REM rebound, which may cause sleep paralysis 
• A family history of sleep paralysis
• People who have traits of imaginativeness and disassociating, such as daydreaming
• Mental stress
• Sleeping on the back
• The use of certain medications

Sleep paralysis is diagnosed with a patient history and physical exam. Tests or procedures that may be used to diagnose sleep paralysis or to rule out other underlying conditions include: 

• Sleep diary
• Sleep study (polysomnography)
• Multiple sleep latency test (MSLT) for daytime sleepiness 
• Record of activity and movement with a monitor or motion detector, usually worn on the wrist throughout the day and night (actigraphy)
• Melatonin sampling 
• Core body temperature measurements 
• Hormone tests
• Electrocardiogram (“ECG”) 
• Computerized tomography (CT) scan 
• Magnetic resonance imaging (MRI) of the brain 
• Pulmonary function tests

Treatment for parasomnias includes:

• Improving sleep hygiene
• Follow the same schedule for going to bed and waking up every day, including on weekends
• Have a set bedtime routine to help relax 
• Ensure your mattress and pillow is comfortable
• Keep the room quiet and dark
• Limit alcohol and caffeine, especially in the evening
• Don’t use electronic devices, including cell phones, for at least a half-hour before bed
• Cognitive behavioral therapy for insomnia (CBT-I), a type of talk therapy used to help to reframe negative thoughts and emotions that diminish sleep
• If sleep deprivation is the cause, try to get at least six to eight hours of sleep each night
• Medication to treat psychiatric illness
• Antidepressants, which can reduce or eliminate dream sleep