National Sleep Foundation

Chapter 6: Parasomnias

What Are Sleep-related Hallucinations?

Sleep-related hallucinations occur at sleep onset (hypnagogic) or upon awakening (hypnopompic) from sleep and can be perceived as very real and frightening.1 The hallucinations consist predominantly of complex visual images, although auditory, tactile, or kinetic events may occur. They can remain present for many minutes, but will usually disappear, often with an increase in ambient light.2 Hallucinations may be associated with narcolepsy.


  1. American Academy of Sleep Medicine. The international classification of sleep disorders: diagnostic and coding manual. 2nd ed. Westchester, Ill: American Academy of Sleep Medicine; 2005.
  2. Silber MH, Hansen MR, Girish M. Complex nocturnal visual hallucinations. Sleep Med. 2005;6:363-366.