High prevalence of isolated sleep paralysis: kanashibari phenomenon in Japan.
Kazuhiko Fukuda, Akio Miyasita, Maki Inugami, K Ishihara
Sleep June 1987 DOI: 10.1093/sleep/10.3.279 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Survey (questionnaire study) Peer reviewed |
|---|---|
| Sample size | 635 |
| Population | Japanese college students (390 men and 245 women) |
| Key findings | About 40% of 635 Japanese college students reported at least one episode of kanashibari, which the authors equate with isolated sleep paralysis, suggesting the phenomenon is more common than usually appreciated. Roughly half of those affected reported preceding physical or psychological stress or a disturbed sleep-wake cycle, and many first experienced it in adolescence, with an earlier peak age of first attack in women than in men. The authors propose that exogenous physical or psychological load and endogenous biological development both influence its occurrence. |
Abstract
In Japan, a set of experiences called kanashibari is considered identical with isolated sleep paralysis. We investigated this phenomenon by means of a questionnaire administered to 635 college students (390 men and 245 women). Of all subjects, about 40% had experienced at least one episode of kanashibari [subjects of K(+)]. Therefore, isolated sleep paralysis is apparently a more common phenomenon than is usually appreciated. About half of the subjects of K(+) reported that they had been under "physical or psychological stress" or in a "disturbed sleep and wakefulness cycle" immediately before the episode. Many subjects of K(+) experienced the first episode in adolescence. In the distribution of age of first attack, the peak occurred at an earlier age in women subjects than in men subjects. These findings suggest that two factors influence the occurrence of the phenomenon. One is exogenous physical or psychological load and the other is endogenous biological development.