Hypnogogic hallucinations are brief hallucinations that take place as you’re falling asleep. They’re common and usually nothing to worry about. They’re usually visual in nature, such as images of patterns, shapes or flashing lights.
Hypnogogic hallucinations are hallucinations that happen as you’re falling asleep. They’re common and usually not a cause for concern. Up to 70% of people experience them at least once.
A hallucination is a false perception of objects or events involving your senses: sight, sound, smell, touch and taste. Hallucinations seem real but they’re not.
Hypnogogic hallucinations are usually brief and fleeting, but are occasionally prolonged. They can take different forms, including:
While hypnagogic hallucinations are a common symptom of narcolepsy, they also occur in people who don’t have narcolepsy.
If you experience hallucinations during the day or night when you’re wide awake in addition to hypnogogic hallucinations, it may be a sign of a mental health disorder or neurological condition.
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Hypnagogic and hypnopompic hallucinations are both sleep-related hallucinations. Hypnogogic hallucinations happen as you’re falling asleep and hypnopompic hallucinations happen as you’re waking up. Both types aren’t usually a cause for concern.
It can be easy to confuse a hypnogogic hallucination with a dream, but they’re different.
You can tell the difference because dreams typically have a storyline, whereas hypnogogic hallucinations are typically brief images or sounds.
In addition, you’ll likely know instantly when you wake up from a dream or nightmare that you were just dreaming but aren't anymore. Hypnogogic hallucinations happen while you’re still awake — albeit almost asleep — and it may take some time to figure out what’s real and what isn’t.
Researchers aren’t sure what exactly causes hypnagogic hallucinations. But they seem neurologically similar to both daytime hallucinations and dreams.
For most people, hypnagogic hallucinations aren’t associated with a health condition and are considered harmless. However, hypnagogic hallucinations are more common in people with certain sleep disorders and health conditions, including:
People who take tricyclic antidepressants are also more likely to experience hypnagogic hallucinations.
If hypnogogic hallucinations are causing you distress, you should talk to your healthcare provider.
Although having a hallucination as you fall asleep might make you feel confused or scared, hypnagogic hallucinations are relatively common and likely not something to worry about.
It’s important to know that hypnogogic hallucinations are different from hallucinations associated with mental health conditions, such as schizophrenia, and neurological conditions, such as Alzheimer’s disease and Parkinson’s disease.
People with these conditions experience hallucinations during the day when they’re wide awake, and have other significant signs and symptoms of the condition.
Hypnogogic hallucinations may or may not need treatment. They may decrease in frequency if you do the following:
If the hallucinations are causing you distress or anxiety, it’s important to talk to your healthcare provider. They may prescribe medications to help you or change any current medications you may be taking that could be causing the hallucinations.
Your healthcare provider can also determine if the hypnogogic hallucinations are a sign of a health condition, such as narcolepsy. If so, the underlying condition will need treatment.
A note from Cleveland Clinic
While experiencing a hallucination while you’re drifting to sleep can feel scary or bizarre, it’s usually nothing to worry about. Hypnogogic hallucinations are common and can happen to people who don’t have any underlying health conditions. If the hallucinations are causing anxiety or you have other symptoms — especially sleep-related symptoms — talk to your healthcare provider. They’re available to help you with your health concerns.
Last reviewed by a Cleveland Clinic medical professional on 06/10/2022.
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