Hallucination is a form of parasomnia event which a person experienced visual, auditory, or tactile sensory perception just before falling asleep or when he is starting to wake up. These visual or auditory images tend to be very vivid and disturbing.

Types of sleep-related hallucinations:

  • Hypnogogic – occurs just before sleep.
  • Hypnopompic – occurs upon waking.

Both hallucinations are often accompanied by sleep paralysis, a state in which the person is fully aware of the surroundings but physically immobile for a brief moment.

Common sleep-related hallucinations:

  • Someone calling your name or hearing voices
  • Floating or falling sensation
  • Out of body experiences
  • Out of scale, distorted, or unrealistic images
  • Sensed presence in a room

These sensations often startle the person and cause awakening with a sudden jerk. They can be frightening and unsettling for the person who experienced them. Hallucinations can cause confusion, as they are difficult to distinguish from reality in the mind.


  • Sleep deprivation, insomnia
  • Extreme stress or anxiety
  • Certain medication
  • Drug or alcohol abuse
  • Developing minds in young children
  • Narcolepsy, a chronic sleep disorder with overwhelming daytime drowsiness and sudden attacks of sleep.

Sleep-related hallucinations are common but occur very rarely and do not need treatment. If the hallucinations are frequent and affect sleep quality, it may be a sign of underlying health condition which requires treatment. Hallucinations derived from lack of sleep or severe stress generally stops after the cause has been eliminated. You may want to see a doctor or sleep specialist if the hallucinations are frequent, or causing you distress and anxiety.

We offer hospital-based and home-based sleep study for your convenience. Consult our senior specialist Dr YT Pang at CENTAS for an accurate diagnosis of your sleep problem.