Sleep paralysis episodes typically occur either early in the night, as someone is falling asleep, or towards the end of the night, as someone is waking up. Stressful life events, anxiety, sleep quality and genetics are all linked to it.

睡眠瘫痪症通常发生在晚间刚入睡时，或者凌晨正要苏醒时。生活压力、焦虑情绪、睡眠质量、以及基因遗传都与之相关。

In a recent UK study, nearly 30 per cent of respondents said that they had experienced at least one episode of sleep paralysis in their lifetime. 

在英国最近的一次调查中，近30%的受访者称曾经经历过至少一次睡眠瘫痪症。