Sleep-related hallucinations are a type of parasomnia, which is typically unpleasant/unreal. Although the most common sleep-related hallucinations are visual, they can also be auditory or tactile. They can happen while falling asleep or awakening. They are called hypnopompic hallucinations when they occur during awakening. Hallucinations that occur during falling asleep are called hypnagogic. Hypnagogic hallucinations are often experienced during the REM phase of sleep.
