Sleep paralysis

Sleep paralysis is the inability to move or speak while falling asleep or waking up. It occurs when the brain sends signals that relax the muscles in the arms and legs, temporarily paralysing them. During an episode of sleep paralysis (usually lasting from a few seconds to a few minutes) the individual may regain awareness but be unable to move, although they can still move their eyes and breathe normally (NHS, 2023). During an episode, many people see, hear, feel and even smell things that are not there; these are referred to as hallucinations. Hypnagogic hallucinations are imagery that take place when falling asleep, whereas hypnopompic hallucinations occur upon waking (Suni, 2023). Although sleep paralysis can be frightening, it is generally considered harmless, and many people (around 7.6% of the general population) will experience it at least once in their lifetime (Sharpless and Barber, 2011).

Sleep paralysis is a

Symptoms of sleep paralysis can include:

• paralysis in the limbs/inability to move
• inability to speak
• sensation of suffocation/tightening around the throat, some individuals report feelings of choking
• hallucinations – including visual, auditory, tactile (false sensation of touch), kinaesthetic (the sensation of movement of a part of the body in the absence of movement) and olfactory (smell) hallucinations. The most common hallucinations are visual and auditory.
• fear – some people report feeling an evil presence or impending doom.
• panic
• helplessness
• daytime sleepiness (Cleveland Clinic, 2021)

Sleep paralysis hallucinations often fall into the following three main categories:

Sleep paralysis has been linked with the following risk factors:

• sleep deprivation or insomnia
• disturbed/irregular sleeping patterns (shift work or jet lag)
• narcolepsy
• night-time leg cramps
• mental health conditions – post-traumatic stress disorder, generalised anxiety disorder, panic disorder, depression
• stress
• sleeping in a supine position (on the back)
• substance abuse and use of certain medications
• family history of sleep paralysis (Farooq and Anjum, 2022)

While the exact cause of sleep paralysis remains unknown, theories about its origin have been proposed. One of the most common explanations relates to a stage of sleep known as rapid eye-movement (REM) sleep – when people tend to have vivid dreams. To prevent the person from acting out their dreams in reality and potentially injuring themselves, the brain sends signals that relax muscles in the limbs, temporarily paralysing the body and preventing movement. Muscle paralysis during REM sleep is a normal part of dreaming sleep, but issues associated with sleep paralysis occur when the dreams during REM sleep spill over into emerging wakefulness (Farooq and Anjum, 2022).

If the individual finds themselves unable to move or speak for a few seconds or minutes when falling asleep or waking up, and this has happened more than once, then it is likely that they have recurrent sleep paralysis (American Academy of Sleep Medicine, 2021).

There are currently no cures for sleep paralysis. However, in many cases, sleep paralysis occurs as a one-off episode and requires no action. If the episodes are recurrent and cause significant disruption or distress for the individual, a number of management techniques have had varying success in improving symptoms: