Home » Sleep Disorders » Parasomnias » Sleep Hallucinations

Sleep Hallucinations

Sleep hallucinations belong to a classification of sleep disorders called parasomnias. They are vivid experiences, either sensory or visual, that occur between the state of waking up and falling asleep. These are imagined incidents that appear very realistic, causing immense fear and anxiety for the person experiencing them. Sleep hallucinations can involve a variety of realistic images such as stagnant items, intense terrifying movements (falling, running or hiding), or the feeling that someone else is in the room with you.

Types of Hallucinations

There are two kinds of sleep hallucinations; hypnagogic and hypnopompic.

Hypnagogic hallucinations occur just as someone transitions from wakefulness to a sleep state. This involves bizarre images and sounds of things or people that aren’t actually in the room. This is the most common type between the two. In fact, one in four people acquire episodes of hypnagogic hallucinations at night.

Hypnopompic hallucinations, on the other hand, occur from the sleep state to wakefulness, or when someone is about to wake up. Just like hypnagogic hallucinations, this type involves imagined images and events that feel very real but aren’t present. This is less common than hypnagogic hallucinations.

Difference between Hallucinations and Dreams

Although both appear to be similar, hallucinations differ greatly from dreams. Dreams happen during the state of sleep. Waking up from a dream during REM sleep instantly lets you recognize that everything happened while you were asleep.

Visual hallucinations, on the other hand, occur between the state of sleep and wakefulness. You are not sure if you were awake or asleep during the episode. However, you are sure that everything that just went down happened in the vicinity of your bedroom.

You may also confuse nightmares with hallucinations but just like dreams, you wake up from a nightmare knowing that it wasn’t real. It all happened while you were shut-eye. The same cannot be said with hallucinations.

What causes hallucinations?

Sleep-related hallucinations may be caused by a variety of factors such as:

  • Alcohol abuse
  • Drug abuse
  • Insomnia
  • Stress
  • Anxiety
  • Trauma

In some cases your hallucinations may happen during the day. This may be an indication that you have narcolepsy. People with narcolepsy may have sudden circumstances of the following during daytime:

  • Sleep paralysis
  • Falling asleep all of a sudden
  • Hypnagogic hallucinations

Parkinson’s disease or schizophrenia could also be the cause of sleep-related hallucinations.


Sleep-related hallucinations are usually linked to an underlying sleep disorder such as narcolepsy. Because of this it is best to see a sleep specialist to examine your health and sleep patterns, especially when your hallucinations have been causing you immense anxiety and fear.

Polysomnogram is a great instrument to study your sleep. Polysomnogram is a type of exam used to measure brain waves. Also known as a sleep study, this also records your:

  • Heart rate
  • Breathing
  • Blood oxygen level
  • Leg and eye movements

Polysomnogram can help your doctor identify what causes your sleep disruption. Your doctor may also recommend a change in your sleeping patterns to lessen the episodes of your hallucinations.


It is important to remember that to stop your hallucinations you have to monitor what causes them. If you are an alcoholic who suffers regular episodes or someone who takes medications or drugs, discontinuing and lessening your intake may help put a stop to your hallucinations. If you have an underlying sleep disorder talk to a sleep specialist to get it treated.

Additional resources:

[optin-cat id=6084]