Sleep paralysis occurs when a person passes between stages of wakefulness and sleep. During these transitions, the sleeper may be unable to move or speak for a few seconds up to a few minutes. Some people may also feel pressure or a sense of choking. Sleep paralysis may accompany other sleep disorders such as narcolepsy. Sleep paralysis usually occurs while falling asleep and while waking. Follow the links below to find WebMD's comprehensive coverage about sleep paralysis, when and why sleep paralysis occurs, how to treat it, and much more.