Sleep paralysis

Sleep paralysis, nightmares and REM sleep behaviour disorder (RBD) are disorders arising from REM sleep.

Sleep paralysis and nightmares are recalled by the patient.

REM behaviour episodes are sometimes recalled but more often only apparent to the bed partner.

Sleep paralysis is a brief state of involuntary immobility usually occurring on waking from a night’s sleep or a nap (more rarely at sleep onset)

• sleep paralysis occurs during the transition between sleep and wakefullness
• patient is fully awake but unable to move except to breathe and move the eyes
• often accompanied by dream imagery, sometimes of a frightening kind
• attributed to waking abruptly from a REM sleep episode with the REM atonia persisting briefly
• appears to be more common in those with narcolepsy, and in those with irregular sleep-wake routine and after drinking alcohol

The attack may terminate spontaneously or following a stimulus such as a touch or a sound.

Reference:

• Wilson S et al. British Association for Psychopharmacology consensus statement on evidence-based treatment of insomnia, parasomnias and circadian rhythm disorders: An update. J Psychopharmacol. 2019 Aug;33(8):923-947
• Zanigi S et al. REM behaviour disorder and neurodegenerative diseases. Sleep Medicine 12 (2011) S54–S58.