Sleep paralysis has two forms and usually lasts from a few seconds up to 2 minutes. It is unpleasant, but, according to modern ideas, harmless. In the first case, it occurs when falling asleep, in the moment of conscious brain falling into REM sleep (normal sleep, the brain stops the function of vigilance of a few seconds before the paralysis, thus people almost never remembers falling asleep). This paralysis is accompanied by catatonic or rather, dissociative manifestations, which are expressed in full or partial awareness of the body scheme and motor skills (e.g., feeling that to move my finger, but the transition from thought to movement lasts indefinitely). The second and most common form of sleep paralysis occurs upon awakening. She is accompanied by such symptoms as feeling reckless fear (fear of death, of the descent into lethargy, nightmares and hallucinations auditive of someone's voice, presence, in close proximity to an outsider, a hostile entity), choking and short of breath, disorientation in space, about body movements (person may feel that he flips from one side to the other, though actually lies on the site), palpitations.