The two types of hallucinations associated with the sleep/wake process are sleep paralysis and hypnagogic hallucinations. They are both very different. Sleep paralysis is when your body is temporarily paralyzed just before falling asleep or right before you wake up. People can't move, speak or react. This is due to muscle weakness and it also sometimes cause people to have severe hallucinations, such as someone breaking into their room and not being able to do anything about it because of the paralysis. Hypnagogic hallucinations on the other hand are when someone is falling asleep. This is often associated with narcolepsy and it causes people to see and hear things that are not actually there. They are usually extremely vivid and realistic.
