If you have ever woken from sleep and felt as if someone were in the room with you, you may have had a sleep hallucination.
Often correlated with sleep paralysis, hallucinations can happen when you are falling asleep or waking from sleep – when there is a disturbance as your brain moves through the different stages of sleep.
Sleep hallucinations are not necessarily an indication of mental illness, and they are actually fairly common, affecting nearly 40% of adults.
These hallucinations are frequently correlated with other sleep disorders, and they can be triggered by a variety of different things.
In this article, we’ll explore the topic of sleep hallucinations in depth, providing an overview of what they are, what causes them, and how they are related to other sleep disorders.
We’ll also provide information about diagnosis and treatment options.
What is Sleep Hallucination?
The word hallucination is derived from a Latin term meaning “to wander mentally.” Hallucinations may involve seeing, hearing, feeling, or even tasting or smelling things that are not real.
Another definition is a sensory experience that is not caused by the stimulation of the relevant sensory organs.
Hallucinations are most commonly associated with schizophrenia, a form of mental illness characterized by delusions, incoherence, and extreme agitation in addition to hallucinations.
They can also occur with bipolar disorder, both type 1 and type 2. When hallucinations occur in the transition between sleep and waking, however, they are called sleep hallucinations.
Depending on the stage of sleep in which the hallucinations occur, they may be either hypnagogic or hypnopompic.
Before getting into the details about sleep hallucination, let’s take a closer look at the five different types of hallucinations:
- Auditory – The most common type of hallucination, you might hear voices or sounds.
- Visual – The second most common type of hallucination, you might see shapes, colors, people, or objects that aren’t really there.
- Tactile – You might feel a sensation that isn’t real such as being touched or having bugs crawling across your skin.
- Taste – You may experience a taste in your mouth that is not real – this type is rare.
- Olfactory – You might smell something that has no physical source.
Hypnagogic hallucinations are those which occur while you are falling asleep. In most cases, these sleep hallucinations are tactile or visual, commonly involving the perception of sounds or sights that aren’t real. This type of hallucination is twice as common as hypnopompic hallucination and they are a common symptom of narcolepsy.
Hypnopompic hallucinations occur during the transition between sleep and wakefulness, and they may include sights, sounds, and sensations. The lifetime prevalence of this type of hallucination is between 6% and 13% while researchers believe that most adults will experience at least one hypnagogic hallucination in their lifetime.
What Are the Symptoms of Sleep Hallucinations?
It’s easy to confuse sleep hallucinations with dreaming because they occur during the transition between waking and sleep. You might even find yourself wondering whether you are awake or asleep. In some cases, sleep hallucinations can be similar to nightmares except for the fact that when you wake up from a nightmare, you are generally aware that it happened while you were asleep.
Some of the most common symptoms of sleep hallucinations include the following:
- Vivid hallucinations while falling asleep or before falling asleep
- Hallucinations that occur while you are waking up
- A feeling as if you are still moving while your body remains still
- Perceptions of sights or sounds that aren’t real
- A sensation of falling or flying
- Images of people, animals, or moving objects in the room
In addition to these hallucinations, people who experience them may experience fragmented sleep which can then lead to excessive daytime sleepiness. A common symptom of several sleep disorders, excessive daytime sleepiness can impact your ability to fulfill daily obligations at work or school, and it could increase your risk for having an accident.
Sleep hallucinations are very similar to sleep paralysis for some people. Sleep paralysis is an episode during which you are unable to move or speak but can still breathe normally.
These episodes usually occur in the transition periods between waking and sleep. For some, they are very brief and only mildly concerning, but some people experience hallucinations during these episodes which can be very scary.
If you experience hypnagogic hallucinations during the day, it could be a sign of narcolepsy. Other symptoms of narcolepsy include excessive daytime sleepiness, uncontrollable attacks of sleep, and sleep paralysis.
If you have these symptoms, consider talking to your doctor about your concerns.
What Causes Sleep Hallucinations?
For many years, sleep hallucinations and sleep paralysis were associated with mental illness. After all, seeing or hearing things that aren’t there are symptoms of psychiatric disorders like schizophrenia and bipolar disorder.
Researchers now know, however, that these hallucinations can occur in people who do not suffer from mental illness, though having anxiety, depression, or bipolar disorder doubles your risk for experiencing sleep hallucinations.
The underlying cause for sleep hallucinations is a hitch in the transition between the different stages of sleep. There are four stages of sleep – three non-REM stages and REM sleep.
The first stage is the lightest stage of non-REM sleep which can be easily disrupted.
As your body relaxes and your brain activity slows, you move into the second stage where brain waves slow down more with specific bursts of rapid activity called sleep spindles. Deep NREM sleep is the third stage and the most restorative of the four, consisting of slow delta waves.
The fourth stage of sleep is characterized by rapid eye movement which is why it is called REM sleep.
This is the dreaming state, so you are most likely to experience sleep hallucinations and sleep paralysis in the transition into and out of this state.
Again, hypnagogic hallucinations occur while you are falling asleep and hypnopompic hallucinations happen as you are waking up.
In most cases, sleep hallucinations are mild, but they can be complex – in these cases, they may suggest the presence of some kind of visual or neurologic disorder.
Aside from psychiatric disorders like bipolar disorder and schizophrenia, having a concurrent sleep disorder or certain other medical conditions can trigger sleep hallucinations.
The use of certain medications or the overuse or abuse of drugs and alcohol might be a trigger as well.
Even if you’re not currently using drugs or alcohol on a regular basis, it could still be a trigger for sleep hallucinations. Sleep hallucinations can also be related to insomnia and sleep deprivation.
Sleep deprivation is both a trigger and a symptom of sleep hallucinations. When you don’t get adequate sleep to meet your needs, you may experience excessive daytime sleepiness.
In severe cases, you may find yourself falling asleep involuntarily during the day, and you could experience sleep hallucinations during the transition into that sleep. The more sleep-deprived you are, the higher your risk for hallucinations.
In most cases related to sleep deprivation, hallucinations are visual, and they can be either simple or complex.
Sleep deprivation can also contribute to other symptoms such as disorientation and paranoia – these symptoms mimic those of certain mental illnesses like schizophrenia. Fortunately, these symptoms are typically resolved when your sleep deprivation is resolved. In fact, some evidence suggests that a single night of adequate sleep may be enough to reverse the negative effects of sleep deprivation, including hallucinations.
If you experience sleep hallucinations on a regular basis, you should talk to your doctor about your concerns. A single episode of hallucination may not be cause for concern, but if you also experience symptoms such as disorientation or paranoia, it could be the result of an underlying condition.
How is Sleep Hallucination Diagnosed?
Generally speaking, sleep hallucinations are fairly common – they have been reported in as many as 33% of all people. Sleep hallucinations are more common in teens and young adults and in women than in men. Some of the factors which may increase your risk for sleep hallucinations include drug use, alcohol use (past or current), anxiety, mood disorders, and insomnia.
Sleep hallucinations are often linked to other sleep disorders, so one of the primary goals of diagnosis is identifying or ruling out underlying conditions. To start, your doctor will take a thorough health history and perform a physical exam to determine whether there are any underlying factors at play. The more information you can provide about your symptoms, the better – your doctor may even ask you to keep a sleep diary for a week or more to track your symptoms and sleeping habits.
Here are some of the things you should keep track of to tell your doctor:
- How much sleep you tend to get on an average night
- Your sleep schedule – when you go to bed and when you wake up
- How you feel in the morning, whether your sleep was restful
- Whether you woke up during the night and, if so, whether you feel back asleep
- How often you experience sleep hallucinations
- When you experienced your first sleep hallucination
- At what point during the night the sleep hallucinations tend to occur
- How long the hallucinations last and which sensations are involved
- Any other sleep-related symptoms or problems
In some cases, your doctor may refer you to a sleep specialist who may then ask you to complete an overnight sleep study including a polysomnogram.
A polysomnogram is a sleep study that measures your brain activity, heart rate, breathing, body temperature, and other metrics while you sleep.
The goal is to identify fragmented sleep patterns that could indicate a sleep disorder or another underlying condition. You may also need additional testing such as an MRI or a Multiple Sleep Latency Test (MSLT).
This test simply measures how long it takes you to fall asleep.
What Are the Treatment Options for Sleep Hallucinations?
Sleep hallucinations are not dangerous to your health, though the experience can certainly be concerning. Depending how often you experience sleep hallucinations, no treatment may be necessary.
If you can easily identify the trigger for your sleep hallucinations, taking steps to avoid that trigger might be all you need to do.
For example, if you experienced a sleep hallucination after sleeping poorly for a few days, you might assume that sleep deprivation was the trigger and catching up on sleep the best resolution.
If you experience sleep hallucinations somewhat regularly, it is possible that the frequency will decrease over time. Doing the following things may help speed that process along:
- Sticking to a regular sleep schedule for bedtime and waking
- Getting an adequate amount of sleep every night (about 7 to 9 hours)
- Avoiding drug use and certain medications
- Moderating your alcohol intake and avoiding alcohol before bed
- Taking steps to reduce your stress such as meditation or relaxation exercises
- Engage in talk therapy to work through stress and other potential triggers
Sleep hallucinations occur during the transition between sleeping and wakefulness.
Anything that interferes with your brain’s ability to move smoothly through that transition can trigger a sleep hallucination. The best thing you can do is get as much sleep as possible and to make sure that the sleep you do get is restful.
Disclaimer: The information on this website is not intended to be used as a substitute for professional medical advice, clinical diagnosis, or treatment. Always seek the advice of your personal physician or another qualified health provider with any questions you may have regarding a medical condition.