Hypnagogic Hallucinations - Incredible Imagery At Sleep Onset

Hypnagogic hallucinations (also referred to as HH, or hypnagogic imagery) consists of imagery experienced at the onset of sleep. Conversely, such imagery experienced upon awakening is known as hypnopompic imagery (although see the usage note just below).

Usage Note

In some cases, including on this site, you may see hypnagogic hallucinations used to cover both hypnopompic hallucinations (when waking up) and hypnagogic ones (when falling asleep).

This is largely a matter of convenience, as many conditions--such as sleep paralysis--can involve both hypnagogic and hypnopompic hallucinations. By referring to them both with the umbrella-term hypnagogic, the writer can facilitate communication and limit the bulkiness of the terms in his or her sentences.

For the most part, this imagery is common to nearly all of us (if we're perceptive enough to notice it) and consists of vague and disconnected images, sometimes splotches of color, that appear oh-so-fleetingly as we fall asleep.

In more fascinating instances of hypnagogic hallucinations, the imagery experienced can be extraordinarily vivid and life-like. In many cases, such vivid imagery can be incredibly frightening for the individual experiencing it, especially when coupled with sleep paralysis. Examples of hallucinations during episodes of sleep paralysis can be found in the stories listed below.

Vivid hypnagogic hallucinations are also one of the four main symptoms of narcolepsy, which you can learn more about here.

Stories Involving Hypnagogic Hallucinations

The following are some visitor-submitted stories involving cases of hypnagogic hallucinations. Browse through them to get a better sense of the incredible nature of some of this imagery, as well as the frightening potential. They are nothing short of testament to the extraordinary capabilities of our mind to create.


Hallucinations While Driving - Sleep Disorder Or Something Else?  Hi, I don't know where to start off, so I'll just start with the basics. My name is "G." I found your site this morning after doing a search on hallucinations ...

Treatment For Hypnagogic Hallucinations Without Narcolepsy?  I am a 59 year old Caucasian female in relatively good health. Approximately 20 years ago, after a sleep lab evaluation, I was diagnosed with Hypnagogic ...

Dream Ebullition and Sleep Paralysis - What Happens?  Hello, I'm 21 years old and I am Brazilian. After much searching on the internet I came to this Stanford University website (I read in Brazilian Wikipedia ...

Read more stories

If you have a story involving hypnagogic hallucinations and would like to share it, we would love to hear it. If it involves sleep paralysis, you can submit it here. If it involves narcolepsy, please submit it here. If it involves neither, please submit it here.

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About This Site

Welcome! This site is continuously being created by students of Dr. William C. Dement's Sleep And Dreams course at Stanford University.

We made this site as a call to action for people all over the world to live healthier, happier, safer, and more productive lives by learning about their own sleep. We have faith that reading the information provided on this site will motivate you to be smart about your sleep deprivation and strategic about your alertness in order to live life to your fullest, most energetic potential.

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The Stanford Sleep Book

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Dr. Dement's pioneering textbook has been the core text for Sleep and Dreams since 1980, but it has just recently been made available to the wider public for the first time.

In it you'll find a more detailed account of the most important things you need to know about sleep, alertness, dreams, and sleep disorders. Studies, statistics, plus plenty of Dr. Dement's classic anecdotes painting the history of sleep medicine.

Preface | Intro | Contents | Get A Copy

More Sleep Resources

The Zeo

A revolution in personal sleep tracking, the Zeo is a wireless headband that transmits your brainwaves in realtime to a dock (pictured here) or your smartphone. The result? You can wake up and see exactly what stages of sleep you were in during the night! Unprecedented personalized sleep knowledge.

Sleep Paralysis: A Dreamer's Guide

Sleep Paralysis Treatment Book

Ever woken up paralyzed? A surprising number of us have, believe it or not. But few know the actual causes of this phenomenon, and fewer still how to exert control over it. Dream researcher and sleep paralysis expert Ryan Hurd shares breakthrough insights into how to do just that.

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