The term ‘Sleep Paralysis’ can describe a range of experiences. These can be varied, though the core symptoms are consistent across cultures. In her excellent book Sleep Paralysis: Night-Mares, Nocebos, and the Mind-Body Connection, Shelley Adler provides comprehensive coverage of the associated symptoms. These are summerised below. For an episode to be considered sleep paralysis only symptoms 1-3 may be present. Symptoms 4-9 may or may not be present, in varying degrees of severity.
1. Being ‘Awake’
Those affected report feeling consciously awake during sleep paralysis experiences. It is experienced as part of waking consciousness, not as a dream.
2. Realistic Perception of Environment
The immediate environment surrounding the bed is clearly perceived. Distinctive elements in the room are observed (e.g. a sleeping partner or a clock).
3. Inability to move
The sense of paralysis is one of the first elements of the experience noticed by the individual. Sometimes this paralysis is attributed to an outside force.
4. Overwhelming fear and dread
A sense of overwhelming fear can accompany the experience. This can be felt so strongly that those who experience it may later struggle to articulate its intensity. Sometimes feelings progress from a sense of foreboding to complete terror and may include feelings linked to death or dying.
5. Sensed presence
Individuals may sense an ‘evil’ or malevolent ‘presence’ in the room with them. This presence may be seen or merely ‘felt’.
6. Chest pressure
The sense of a physical weight being pressed down onto the chest. This can be purely sensual or can seem to be the result of an external presence or force literally pushing down on the chest.
7. Difficulty breathing
This can occur alongside pressure to the chest.
8. Supine position
Most sleep paralysis attacks occur whilst the individual is lying on their back, although studies have shown that generally people tend not to fall asleep in this position.
9. Additional Unusual Sensations
As well as visual hallucinations, sleep paralysis episodes may be accompanied by hallucinations of an auditory, olfactory and/or physical nature. Commonly reported hallucinations include doors opening, animals growling, approaching footsteps, scratching, internal buzzing/beeping, malevolent whispering as well as smells of rotting flesh, ‘death’, decay, damp, mould and feelings of being moved, drifting, rolling, floating, cold or heat. Out-of-body experiences are also sometimes reported.