Sleep paralysis is usually described as the feeling of being awake and conscious but unable to move. It can normally occur as a person is falling asleep or waking up, during the transition between sleep and wake states. It often occurs when a person is waking up from rapid eye movement (REM) sleep, and their muscles are still “turned off” or “partially paralyzed.” It can be frightening, and some people even fear they are experiencing supernatural or out-of-body phenomena. Sleep doctors always consider whether the patient might have narcolepsy. However, the most common factor linked to sleep paralysis is sleep deprivation. Substance use and certain medications can increase the frequency of events. A careful review of your sleep history and habits will usually help identify possible culprits and guide further recommendations.