Prisoners of the Body: The Link Between Interoception and Sleep Paralysis.

Abstract

Sleep paralysis (SP) is a REM sleep parasomnia characterized by transient motor paralysis during sleep onset or awakening. It is a terrifying experience often accompanied by vivid hallucinations. Although it is classically linked to narcolepsy, isolated SP in healthy individuals offers a valuable model to investigate the interaction between REM sleep physiology and conscious awareness. In a sample of 210 adults from the Italian population, we examined the prevalence, phenomenology and cognitive-emotional landscape of SP. Importantly, this study provides preliminary evidence to integrate measures of interoception to investigate how body awareness might influence this experience. One out of four participants reported at least one episode of SP. The most common sensations echoed REM physiology, including the inability to move or speak, tingling and sealed eyelids. However, despite this paralysis, the mind conjured up vivid cognitive scenes and the felt presence of another being, as well as an overpowering fear of death. Contrary to earlier findings, SP was not tied to poorer sleep quality or chronic anxiety. Instead, it was associated with insomnia symptoms and hyper-attuned body awareness. Individuals experiencing SP showed greater interoceptive sensitivity, noticing subtle bodily cues and regulating attention and emotion through them. This convergence between sleep physiology and interoceptive awareness suggests that SP may emerge where the boundaries among body, sleep and consciousness become blurred, a dissociated state in which REM-related atonia coexists with preserved or re-emerging conscious awareness. These findings suggest potential avenues of interoception as a target for future investigations into parasomnias.