If you think you’re seeing — or smelling, hearing, tasting, or feeling — things when you’re asleep, you may not be dreaming. It’s possible you’re experiencing hypnagogic hallucinations. These can occur in the consciousness state between waking and sleeping. Dreams, on the other hand, occur during sleep.
Hypnagogic hallucinations often cause confusion. This is because it can be hard to distinguish hallucination from reality. They create strong, intricate visual images in the mind that may be distorted in an unrealistic way. As a result, these hallucinations often cause fear. In some cases, they can even cause you to jump out of bed or accidentally injure yourself.
A hallucination is defined as perceiving the presence of an object or an event through any of the five senses (sight, smell, taste, touch, or hearing) without the actual object or event existing or occurring.
The defining symptom of a hypnagogic hallucination is imagining very realistic objects or events right before falling asleep (usually visually). You may wake up in extreme fear that your hallucination was real.
Auditory hallucinations are also common when the body is falling asleep. These hallucinations are more common when a person is under stress. Most common auditory hallucinations are simple and don’t have a real meaning or purpose. This can include:
- high-pitched noises
- random noises
- popping noises
- unclear noises
Severe cases of anxiety may produce more complex hallucinations. They may involve voices, which are sometimes associated with rapid thoughts. This can lead a person to believe the voices are real.
Another common type of hallucination is the vision or sensation that bugs are crawling over your body. This is most common in people who take or misuse certain drugs. Experiencing this sensation during sleep may cause a person to scratch, pick, or even cause harm to their body in an attempt to rid it from bugs.
Sleep paralysis and lucid dreams
Hypnagogic hallucinations are different from other sleep-related conditions — including lucid dreams and sleep paralysis — that may cause perception of things that are not real. Lucid dreams are very realistic dreams that occur when a person is asleep.
Sleep paralysis is a separate condition from hypnagogic hallucinations. However, it may occur simultaneously. Sleep paralysis is a state of sleep where a person is physically immobile but mentally conscious. This condition may cause even more fear, as the physical immobility — often difficulty breathing and muscle tightness — can make a person feel as though they’re frozen in place. As a result, a person may remember a sleep paralysis and hallucination episode as a dream where they were frozen in place or unable to move. In reality, it was these two conditions working together.
In one study in the United Kingdom, experts found that about one-third of the population experienced a hypnagogic hallucination at some point in their life. American researchers have put the number at 25 percent.
These hallucinations are more common in teens and young adults, with the number of hallucinations decreasing with age. Females appear more likely to experience these hallucinations than males.
The exact causes of hypnagogic hallucinations are not well understood. Some possible risk factors include:
- alcohol or drug use
- mood disorders such as bipolar disorder or depression
Epileptic seizures may also cause hypnagogic hallucinations. When epilepsy is the cause, hallucinations may appear as short visual fragments.
Hypnagogic hallucinations are harmless in most cases. However, you should see a sleep specialist if these hallucinations cause you anxiety or disrupt you frequently during your sleep. If your hallucinations are accompanied by unusual sleepiness during the day, you should seek a specialist’s help right away, as you might have narcolepsy.
If you seek help from a sleep specialist, they will begin your appointment by asking you questions such as:
- When did your hallucinations begin?
- How often do your hallucinations occur?
- How long do your hallucinations last?
- Do you have any other sleep problems, such as insomnia?
- Are you sleepy during the day?
Besides inquiring about your sleep, a sleep specialist will also ask you about your medical and psychiatric history. Remember to tell them about any past or present drug or medication use.
The sleep specialist may ask you to bring home a sleep diary for two weeks. This helps the specialist gain insight into your sleeping patterns. This insight may help them better diagnose your condition and figure out how to correct it.
The sleep specialist may also recommend a sleep study (polysomnogram) if your hallucinations are intensely disturbing to your sleep. A sleep study involves attaching wires and equipment to your head and body to chart your brain waves, heartbeat, and breathing as you sleep. It also records how your arms and legs move. This kind of study can uncover if your hypnagogic hallucinations are related to any other type of sleep disorder.
The specialist may ask you to do a daytime nap study (multiple sleep latency test) if you are very sleepy during the day. This test measures how quickly you fall asleep during the day, and what kind of sleep you have when you nap. This test can reveal whether or not your hallucinations are related to narcolepsy.
Treating hypnagogic hallucinations requires treating any underlying conditions that may be the cause. Often, hallucinations will decrease over time. They may also decrease if you do the following:
- Focus on getting enough sleep. Recommendations are:
- 8-10 hours for teens ages 14-17
- 7-9 hours for adults ages 18-65
- 7-8 hours for older adults over 65 years
- Keep a regular sleep schedule in which you go to sleep and wake up at the same times daily.
- Avoid alcohol, illicit drugs, and certain medications.
If your hypnagogic hallucinations are caused by anxiety, your doctor may recommend psychiatric treatment. Treatment for anxiety could involve talk therapy, meditation, or medication, as well as other at-home care to reduce stress. If you’re diagnosed with narcolepsy, your sleep specialist will prescribe narcolepsy medications.
In cases of severe hypnagogic hallucinations, people have been known to jump out of bed and accidentally injure themselves. People may also cause themselves harm if they have a hallucination that bugs are crawling on them. So it’s important to seek treatment if your hallucinations are severe.
Often hypnagogic hallucinations resolve on their own over time. If there’s an underlying cause to your hallucinations, seeking treatment for the condition can help prevent future hallucinations from occurring. This will improve your quality of sleep.