When we sleep, our bodies must shut down and literally paralyze our bodies. This is to avoid hurting ourselves or sleepwalking while we're dreaming in REM sleep. Of course, sometimes, our brain doesn't quite register the instant we're awake so if we're disturbed during REM sleep, there is a small chance that you may continue being paralyzed despite having regained consciousness, leading to a frightful period when we experience something like locked-in syndrome. Studies have shown that teens 14-17 are particularly affected by it while older people have fewer bouts of it. There is no cure or proven way to prevent it but, since depression, anxiety, and bipolar disorder can trigger it, by treating that, you may have a lower chance of having it.
Other than literally not being able to move, sleep paralysis may also trigger visual, smell, and auditory hallucinations. This led people in the 1600s to believe that sleep paralysis was a sign of demonic activity or witchcraft. Of course, through in depth science research, we soon found that this was just a transitioning state between REM sleep and wakefulness.
Have you ever experience sleep paralysis or know someone who did/does? How about the opposite, sleep walking?