<unk>  (plural:<unk>  is a state, during waking up or falling asleep, in which a person is aware but unable to move or<unk> eak. During an episode, one may hallucinate (hear, feel, or see things that are not there), which often results in fear. Episodes generally last less than a couple of minutes. It may occur as a single episode or be recurrent. The condition may occur in those who are otherwise healthy or those with narcolepsy, or it may run in families as a result of<unk> ecific genetic changes. The condition can be triggered by sleep deprivation, psychological stress, or abnormal sleep cycles. The underlying mechanism is believed to involve a dysfunction in REM sleep.<unk>  is commonly experienced by lucid dreamers; some lucid dreamers use this as a method of having a lucid dream. Diagnosis is based on a person's description. Other conditions that can present similarly include narcolepsy, atonic seizure, and hypokalemic periodic<unk> . Treatment options for<unk>  have been poorly studied. It is recommended that people be reassured that the condition is common and generally not serious. Other efforts that may be tried include sleep hygiene, cognitive behavioral therapy, and antidepressants. Between 8% and 50% of people experience<unk>  at some point in their life. About 5% of people have regular episodes. Males and females are affected equally.<unk>  has been described throughout history. It is believed to have played a role in the creation of stories about alien abduction and other paranormal events.
Sleep paralysis
Narcolepsy
Sedation
Night terror
Sleep disorder
Hypokalemic periodic paralysis
Syncope 
Atonic seizure