Hypnagogic hallucinations, also sometimes referred to as waking dreams, are a type of hallucination that occurs as a person is drifting off to sleep. In general, hallucinations involve seeing, hearing, feeling, or smelling something that isn’t actually present. Hypnagogic hallucinations primarily involve seeing things that aren’t there.
Although having a hallucination might prompt confusion or fear, hypnagogic hallucinations are relatively common and likely not something to worry about. Hypnagogic hallucinations are a common symptom of narcolepsy, but they also occur in people who don’t have narcolepsy. In fact, one study found that 37% of people report experiencing hallucinations as they fall asleep.
Learn more about hypnagogic hallucinations, how they differ from hallucinations caused by mental health disorders, their symptoms, their causes, and if you should do anything to stop having them.
What Are Hypnagogic Hallucinations?
Hypnagogic hallucinations are hallucinations that happen as you’re falling asleep. Generally, these hallucinations are short-lasting and straightforward. Eighty-six percent of these hallucinations are visual in nature. People commonly see moving patterns and shapes, or vivid images of faces, animals, or scenes. Up to 35% of hypnagogic hallucinations involve hearing sounds, such as voices or music. In 25% to 44% of cases, a person experiencing a hypnagogic hallucination feels a physical sensation, like they’re falling or weightless.
People experiencing hypnagogic hallucinations for the first time might feel confused about what they are experiencing. Thankfully, hypnagogic hallucinations aren’t usually any cause for concern. They are different from the hallucinations associated with mental health disorders, such as schizophrenia. They also differ from nightmares, though they might be more likely to occur in people with certain sleep problems.
Hypnagogic Hallucinations vs. Hallucinations Associated With Mental Health Disorders
Although hypnagogic hallucinations share some similarities with the hallucinations that people with schizophrenia experience, there are some key distinguishing characteristics. Hypnagogic hallucinations are much more likely to be visual, while schizophrenic hallucinations are predominantly auditory. When people have hypnagogic hallucinations, they generally recognize them as hallucinations rather than believe them to be real. Also, people are much more likely to forget about hypnagogic hallucinations than they are schizophrenic hallucinations. Hypnagogic hallucinations usually don’t have a major impact on a person’s life.
If you have hallucinations as you’re falling asleep but do not have any hallucinations during the daytime when you’re wide awake, you likely don’t need to worry that your hallucinations are a symptom of mental illness. People with schizophrenia often hear voices or see people who aren’t there, and they often believe these hallucinations to be real. They also experience many other symptoms, such as paranoid or delusional beliefs, disordered thoughts, and difficulty focusing or speaking.
Although less common, hallucinations sometimes occur in people experiencing other mental health disorders. For example, a minority of people experiencing severe depression, bipolar disorder, postpartum psychosis, post-traumatic stress disorder (PTSD), or borderline personality disorder have hallucinations. If your hallucinations only occur as you fall asleep, they are likely not due to one of these disorders. Also, anyone with one of these mental disorders experiences other symptoms in addition to hallucinations.
Finally, an increase in hypnagogic hallucinations has been found in people taking amitriptyline, a drug used to treat depression. However, doctors don’t view this increase in hypnagogic hallucinations as a problem or a reason to discontinue the medication.
How Do Hypnagogic Hallucinations Differ From Nightmares?
Hypnagogic hallucinations differ from nightmares, but the two do share some similarities. Both hypnagogic hallucinations and nightmares are associated with sleep — neither happens during the daytime when you’re wide awake. Hypnagogic hallucinations occur at night as you fall asleep. Generally, vivid dreams, such as nightmares, occur later in your sleep cycle when you are fully asleep, most commonly during the rapid eye movement (REM) stage.
Nightmares are essentially frightening dreams. People often awaken from a nightmare feeling afraid and remembering what occurred in the dream in vivid detail. Although hypnagogic hallucinations can be frightening on occasion, they aren’t particularly associated with fear. While nightmares involve detailed storylines, hypnagogic hallucinations are usually just a series of moving images, sometimes accompanied by sounds or bodily sensations.
In adults, frequent nightmares are associated with PTSD and other psychiatric conditions, certain medications, and certain sleep disorders. Although hypnagogic hallucinations occur more commonly in people with certain sleep disorders, they are considered normal and common in healthy people.
Although hypnagogic hallucinations and sleep paralysis are two separate phenomena, they can occur simultaneously and might feel like a nightmare. When sleep paralysis occurs, a person feels awake but unable to move their body. During sleep paralysis, a person often hallucinates sounds or sensations, such as that of a person in the room or even on their chest. If sleep paralysis and such hallucinations occur as a person is falling asleep, they are considered hypnagogic hallucinations.
Symptoms of Hypnagogic Hallucinations
Hypnagogic hallucinations are hallucinations that occur as you’re falling asleep. Beyond that, there are no additional symptoms. Hypnagogic hallucinations can be visual, auditory, or sensory in nature. A person can also have a hypnagogic hallucination that is visual, auditory, and sensory at the same time. Research shows the prevalence of each type of hypnagogic hallucination:
- 8% to 34% auditory
- 25% to 44% sensory
Visual hypnagogic hallucinations often involve moving shapes, colors, and images. For example, a hypnagogic hallucination might be similar to looking into a kaleidoscope. Visual images might also include animals, people, faces, and lifelike scenes. These images generally stand alone or move, but they do not involve a story or interaction, like dreams often do.
Auditory hypnagogic hallucinations generally involve background sounds. For example, common auditory hallucinations include sounds of a phone, the ringing of a doorbell, people’s voices talking, or animal noises. Again, these sounds aren’t usually associated with a story like they would be in a dream.
Sensory or tactile hypnagogic hallucinations refer to when a person feels bodily sensations that aren’t actually occurring. For example, you might feel weightless, or like you’re falling. Sometimes people sense that another person is in the room, even though no one is present. This sensory hallucination is commonly associated with sleep paralysis, which can co-occur with hypnagogic hallucinations.
What Causes Hypnagogic Hallucinations?
Experts aren’t entirely sure what causes hypnagogic hallucinations. Neurologically, hypnagogic hallucinations appear to share some similarities with both daytime hallucinations and dreams. Researchers once hypothesized that hypnagogic hallucinations resulted from REM sleep patterns intruding during awakened moments, but research hasn’t substantiated this idea.
For most people, hypnagogic hallucinations aren’t associated with a disorder and are considered harmless. However, hypnagogic hallucinations are more common in people with certain sleep disorders and health conditions. For example, hypnagogic hallucinations are prevalent in people who experience narcolepsy, as well as those with insomnia, excessive daytime sleepiness, and mental health disorders. Because hypnagogic hallucinations are so common, experiencing them doesn’t necessarily indicate you have an underlying disorder.
When Should You See a Doctor?
If you only have hypnagogic hallucinations — brief, simple hallucinations as you’re falling asleep at night — and no further symptoms, you likely don’t need to see a doctor. If your hallucinations happen during the daytime, however, then you should seek medical help. Daytime hallucinations are different and could be the result of a mental health disorder, a medication side effect, or some other issue that requires professional attention.
If you have hypnagogic hallucinations in addition to other symptoms of a sleep disorder, then you should also consider seeking medical attention. Hypnagogic hallucinations are commonly associated with narcolepsy. Other narcolepsy symptoms include excessive daytime sleepiness, sudden loss of muscle tone (cataplexy), sleep paralysis, and trouble sleeping. Narcolepsy is a sleep disorder that can come with serious consequences, such as falling asleep while driving, so treatment is imperative.
How Can You Stop Having Hypnagogic Hallucinations?
If you only have hypnagogic hallucinations on occasion, they are likely not cause for concern. If they are disturbing your sleep or causing you distress, however, see a medical professional. Your doctor can help you determine if your hypnagogic hallucinations are due to an underlying cause, such as a sleep or mental health disorder. If they are, treating that underlying disorder could help alleviate your hallucinations.
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