Sleep-related hallucinations are vivid and intense sensory or visual experiences that may occur either when you are falling asleep or waking up. Hallucinations can involve realistic images of objects, sensations of movement like falling or running, or feeling like someone else is in the room. Although they are mostly visual, they may also involve senses of sound, touch, taste, and smell. All these hallucinations are considered parasomnias which are considered a sleep disorder that becomes active during the transition between sleep stages, or the transition between sleep and wakefulness.

It is easy to confuse them with a state of dreaming. When hallucinating in your sleep, you are not sure whether you are awake or asleep. You may be thinking you are having a nightmare. However, when you wake up from a nightmare, you are certain it occurred while you were asleep, and it’s clearly recognized as a dream. When it comes to sleep hallucinations, you may think they were real.

Sleep-related hallucinations generally occur at one of the two following times:

  •    When you are about to fall asleep (hypnagogic)
  •    When you are about to wake up (hypnopompic)

When sleep hallucinations occur during the day, they may be a symptom of narcolepsy. People with narcolepsy often struggle with sleep attacks (suddenly falling asleep in the middle of any activity, such as driving), sleep paralysis, and hypnagogic hallucinations. The hallucination and the sleep paralysis may occur at the same time but on different nights. These individuals also often experience parasomnias such as sleep talking and sleepwalking (somnambulism).

Complex visual hallucinations such as stationary images of people or animals often occur just after being suddenly awakened. You don’t recall being in the middle of a dream when you wake up. You will know that you are awake. At first, you will feel afraid and think the images you are seeing are real. Some people even jump out of the bed in terror and injure themselves while doing so. The images may be distorted in shape or size, and they are typically present for a few minutes. If the light is turned on, they often go away. Migraines may also cause sleep hallucinations, and in that case, the visual images are followed by sharp head pain.

Prevalence

According to research, sleep-related hallucinations are rare in children, and around 40% of adults experience it. Hallucinations often coexist with other sleep disorders, such as narcolepsy and sleep paralysis.

Symptoms

Common symptoms of sleep-related hallucinations include:

Sleep hallucinations often seem dream-like, but during the delusion, the person is considered awake. Dreams always occur in REM sleep and when a person is fully asleep.

A hallucination is defined as perceiving the presence of an object or an event through any of the five senses without the actual object or event being real or actually occurring. Hallucinations are typically visual, but may also be auditory. Visual hallucinations cause extreme fear and panic. Auditory ones are more frequent when a person undergoes a lot of stress. Typical auditory hallucinations are very simple and rarely don’t include more than sounds of beeping, high-pitched noises, random noises, popping noises or unclear notes.

Severe cases may produce more complex hallucinations such as hearing voices, which are associated with rapid thoughts. This usually leads the person to believe the voices are real.

When it comes to tactile hallucinations, most common are the sensations of bugs and spiders crawling all over the person’s body. This mostly occurs due to alcohol and drug abuse. Experiencing this type of sensation in sleep may make the person feel rather unpleasant, start scratching, picking or even harming their body in an attempt to get rid of the bugs.

Types of Sleep-Related Hallucinations

Sleep hallucination can be either hypnagogic or hypnopompic.

Hypnagogic hallucinations occur while falling asleep, and they are typically visual, auditory or tactile. Hypnagogic hallucinations are twice as more common than hypnopompic hallucinations. They are often a symptom of narcolepsy, but a person without it can also experience hallucinations. Researchers and sleep experts believe most people will experience a hypnagogic type of hallucination at least once in their life.

Hypnopompic hallucinations are common during the transition from sleep to wakefulness. Like hypnagogic hallucinations, these episodes are short-lasting and can be visual, auditory and tactile. Hypnopompic hallucinations are rarer than hypnagogic hallucinations and experienced only by 6 to 13% of adults.

Sleep Paralysis and Lucid Dreams

It’s important to know that sleep-related hallucinations (especially hypnagogic type) are different from other sleep disorders and related conditions such as lucid dreaming and sleep paralysis. Lucid dreaming and sleep paralysis can also cause the perception of things that are not real, but they have nothing to do with hallucinations.

Lucid dreams are very realistic dreams that occur only when a person is asleep, and sleep paralysis is also a separate condition. Sometimes, hypnagogic hallucinations and sleep paralysis can occur simultaneously. During sleep paralysis, the sleeper is immobile but mentally conscious of their surroundings. This may cause fear, anxiety, and due to the physical immobility, the sleeper may have difficulty breathing and experience muscle tightness. Feeling like you are frozen in place may lead to panic and shock. These episodes of sleep paralysis and hypnagogic hallucinations are often remembered as a very vivid dream where they were frozen in place or unable to move. In reality, it was these two conditions working together.

Causes

In the past, sleep-related hallucinations were often associated with mental disease. Today, we know that sleep-related hallucinations may occur without any mental illness. However, people suffering from a mental disease such as depression, anxiety or bipolar disorder are more likely to experience them. Alcohol use, certain medications, brain injury insomnia, sleep deprivation, and stress may also cause sleep-related hallucinations. Just like certain sleep disorders, the risk of sleep-related hallucinations may be inherited.

When it comes to medication, taking tricyclic antidepressants or hallucinogenic drugs like LSD may increase the risk of experiencing sleep-related hallucinations.

Physiology of Sleep-Related Hallucinations

As you probably know by now, during sleep, many parts of our brain are active and working on a lot of different things. During REM sleep, people dream, and we usually have at least three dreams per night, although, most of the times, we don’t remember any. The reasons for dreaming are still not completely understood, but researchers believe this may be a way for the brain to recall memories and sort through information. Some information will be stored into long-term memory, while others will simply be forgotten.

Through the night, our body cycles through different sleep stages multiple times a night. Dreaming and parasomnia, such as sleepwalking and sleep talking, typically occur during deeper stages of sleep. When a person has just fallen asleep or wakes up, they are usually in a phase of light sleep. Sleep disorders like narcolepsy can cause a person to directly enter into deep sleep or to wake up in the middle of slow-wave sleep. Due to this, dreams and sleep-related hallucinations become more vivid and feel more real.

Physicians still don’t know what causes hypnagogic hallucinations in people who do not struggle with narcolepsy. Hypnagogic hallucinations often occur in periods when deeper and lighter sleep overlap.

Diagnosis

Hypnagogic and hypnopompic hallucinations are not dangerous and do not pose a risk to your health. However, if you experience hallucinations, there is probably an underlying health condition that is causing them. If you experience any of the following symptoms, you should visit a doctor.

Symptoms of narcolepsy – muscle weakness, excessive daytime sleepiness, and disturbed sleep at night are the most common signs of this sleep disorder.

Symptoms of schizophrenia – signs include hearing voices, having confused thoughts, and experiencing changes in behavior.

Symptoms of Parkinson’s disease – signs include slow movement, stiff muscles, and shaking hands and shaking in other parts of the body.

Due to severe migraines, a person may start seeing colors, lights or images that don’t exist. These visualizations are also known as auras. They usually occur with the headache and are different from sleep-related hallucinations.

Hypnagogic hallucinations can be very disturbing and cause stress, anxiety, and insomnia. If the illusions are starting to affect your everyday life and activities (if they have become common), you must see a doctor. In most cases, treating the underlying condition will make the hallucinations disappear.

In order to establish whether your hallucinations are linked to a sleep disorder, a sleep specialist will have to evaluate your medical history, sleep history, and sleep patterns. Diagnosing may involve using a polysomnogram, and an overnight sleep study. In some cases, such as when you are having strong migraines, a doctor may request an MRI of the brain.

If you seek help from a sleep specialist, your appointment will begin by having to answer questions such as:

  •    When did your hallucinations start?
  •    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?

After taking information about your sleep, a specialist will ask for more details about your medical and psychiatric history. It is very important to be completely honest and tell them about any past or present drug or medication use.

You will have to track your sleep for two weeks in order to help the doctor get more insight into your sleeping patterns. Tracking your sleep patterns is important for better diagnosing your condition and deciding what treatment is most suitable for it.

If your hallucinations are severely disturbing your sleep, you will probably have to undergo a sleep study. During a sleep study, a specialist will measure your brain, heart and lung activity, and look for fragmented sleep patterns that might indicate an underlying disorder. The activity is measured by using a polysomnogram. Apart from charting your brain waves, heartbeat and breathing, this device also tracks how your arms and legs move during sleep. A sleep study will reveal if any sleep disorders, such as narcolepsy, may be causing your hallucinations.

Apart from keeping a sleep diary and undergoing a sleep study, the doctor may recommend a multiple sleep latency test also known as the daytime nap study. The multiple sleep latency test measures how quickly you fall asleep during the day and what kind of sleep you have when you nap. This test is important because it may reveal whether your hallucinations are caused or related to narcolepsy.

Treatment

Treatment for sleep-related hallucinations depends on their cause. If they are caused by using alcohol, drugs, or medications, discontinuing the usage of these substances will solve the problem and end the hallucinations. In case they are caused by a sleep disorder such as narcolepsy or insomnia, treating those underlying conditions will resolve the unwanted hallucinations. Often, hallucinations will decrease over time, and doing things such as avoiding stress and prioritizing a good night’s rest will also help.

The amount of sleep you need depends on your age. Recommendations are:

  •    8-10 hours for teens (14-17 years old)
  •    7-9 hours for adults ages (18-65 years old)
  •    7-8 hours for older adults, age over 65

Keeping a regular sleep/wake schedule and creating a simple bedtime ritual to unwind before sleep also helps you a lot. Lastly, if you struggle with idiopathic hallucinations, you should avoid alcohol, and drugs that may cause or further aggravate your condition.

In some cases, hypnagogic hallucinations are caused by anxiety. To treat them, your doctor may suggest medication, cognitive behavioral therapy, meditation and similar treatment measures that will help you reduce anxiety and stress. If you have narcolepsy, your family doctor or sleep specialist will prescribe narcolepsy drugs.

If you feel like you can live with your sleep-related hallucinations, you may not need treatment at all. If there is no underlying medical condition, the only thing left to do is to make certain lifestyle changes that may help with lessening the frequency of hallucinations. For example, getting proper rest at night, and avoiding alcohol and certain medications may help. If hallucinations cause disrupted sleep or anxiety, your doctor might prescribe medication.

Complications

As mentioned above, in most cases, sleep-related hallucinations do not affect your overall wellbeing. However, it is best to visit a doctor to be sure. When an underlying medical condition does not cause these hallucinations, they usually do not have long-term or severe complications. Most common effects of hallucinations are insomnia, stress, and anxiety. Sleep hallucinations may disturb not only the affected individual but also their sleep partner and other household members. This typically occurs when the person hallucinating wakes up in terror and starts screaming or shouting. Also, a person experiencing a hallucination injure themselves by falling out of bed and similar. If such issues occur, they definitely pose harm for health and wellbeing, in which case you should consult your doctor for advice or treatment.

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