Hypnagogic state

Hypnagogic state or hypnagogia, is a term that refers to sleep related hallucinations that occur during the transition from wakefulness to sleep (hypnagogic hallucinations) and from sleep to wakefulness (hypnopompic hallucinations) ¹. An example is feeling as if there is a stranger in your bedroom. These hallucinations may be particularly vivid and frightening because you may not be fully asleep when you begin dreaming and you experience your dreams as reality. Hypnagogia are involuntary, spontaneous, of varying emotionality, and are found in up to 70% of the general population ². Recent studies done suggest that these hypnagogic hallucinations occur with considerable frequency within the general population, with estimates ranging from about 39% to 85% ³. Hypnagogic state and hypnopompic hallucinations are common in narcolepsy ⁴. Hypnopompic hallucinations may be a better indicator of narcolepsy than hypnagogic hallucinations in subjects reporting excessive daytime sleepiness ⁴. Hypnagogic and hypnopompic experiences accompanying sleep paralysis are often cited as sources of accounts of supernatural nocturnal assaults and paranormal experiences ⁵.

Visual, auditory and tactile sensations are most commonly reported (alone or co-occurring) ⁶. Individuals report hearing their name called just as they are falling asleep, feeling a presence in the room with them, seeing blurry images, noticing diffuse light, and having out-of-body experiences ³. Visual phenomena occur in 86% of all hypnagogia ⁷ typically consist of kaleidoscopically changing—possibly entoptic—phenomena such as geometric patterns, shapes and light flashes. Images involving animals, people and faces, and scenes also occur and are described as “lifelike,” highly detailed and colorful ⁸. Voices and other sounds (phone, doorbell, music) occur less commonly (8% to 34%) ⁹. They comprise vivid auditory impressions of words or names, people talking, and environmental or animal sounds ¹⁰. Somatic experiences also occur (25% to 44%) ², including bodily distortions, feelings of weightlessness, flying or falling, and a sense of presence in the room ¹¹. Recent studies done suggest that these hypnagogic hallucinations occur with considerable frequency within the general population, with estimates ranging from about 39% to 85% ³.

Hypnopompic hallucinations are usually continuations of dream sequences during the first seconds or minutes of wakefulness ⁸. In contrast to typical dreams, hypnagogic hallucinations are often static – like single snapshots ¹², and usually do not include a self character ¹³. Some activities performed before sleep (e.g. video games) may influence the content of hypnagogic dreams ¹⁴.

Dreaming occurs during a physiological sleep state which is accompanied by a continuous stream of perceptions, thoughts, and emotions ¹⁵. The dreamer typically experiences visual (100%), auditory (40%–60%), and somatic/tactile (15%–30%) percepts, and more rarely, smell, taste, pain, sexual sensations, and proprioceptive or kinesthetic sensations (1%) ¹⁶. Dreams typically feature visual images of people, faces, objects, animals, and scenes that are rich in shape and full of movement ¹⁶. They may have nonsensical or bizarre contents ¹⁷ that are usually readily accepted by the dreamer. Dreams can also include sounds and speech such as conversations with other people or people talking about commonplace, or unrealistic, matters ¹⁸. Dreams of entire scenes are very common. Dreams can evoke a range of intense emotions ¹⁹, congruent with the dream’s content ²⁰.

A key feature of dreams is that they are immersive experiences in which the dreamer is at once actor and spectator ⁸. They may follow a narrative structure, sometimes involving a replay or combination of the day’s events, past experiences and fantastical elements. They are largely beyond the control of the sleeper (except during episodes of lucid dreaming). Finally, since the person is only aware of dream contents upon waking, the phenomenon is necessarily experienced in retrospect. Dreams are predominantly reported from REM sleep, but also happen to a lesser extent during non-REM sleep during which they may have a pseudo-quality that allows the dreamer to distance himself from what he is dreaming.

Hypnagogic state causes

Sleep related hallucinations may be a direct result of alcohol or drug use, or could be due to insomnia, anxiety, stress or other factors. People with narcolepsy have a high rate of sleep hallucination occurrence ²¹.

Though underlying neurobiological mechanisms are still partly unknown, hypnagogic hallucinations and sleep paralysis are usually considered dissociated manifestations of REM sleep, with the hypnagogic hallucinations described as dreamlike intrusions into waking cognition and the latter considered to be the persistence of typical REM muscle atonia into wakefulness ²². Experimental evidence seems to point to the sleep-onset REM period typically found in narcoleptic subjects as a neurophysiological substrate for these phenomena; sleep paralysis has also been found to occur upon awakening during offset REM, confirming the hypothesis of an underlying dissociation of the REM stage in the transition between wakefulness and sleep. From a neurochemical point of view, an imbalance in the monoaminergic -cholinergic modulation of transitions among states of consciousness seems to underpin hypnagogic hallucinations and sleep paralysis by shifting the brain towards cholinergically driven hallucinatory cognition and inhibition of motility. The AIM state space model appears to further explain these REM-related phenomena by interpreting them in terms of varying levels of brain activation (A) and processing of internal–external inputs (I) in addition to neurochemical modulation (M).

It is also important to know if there is something else that is causing these episodes. They may be a result of one of the following:

• Another sleep disorder such as narcolepsy
• A medical condition
• Medication use
• A mental health disorder
• Substance abuse

Risk factors for hypnagogia

Sleep related hallucinations seem to be very common. They have been reported by as many as one-third of all people. They are more common in teens and young adults. In many people the episodes tend to decrease with age. They also occur slightly more often in women than in men. They are very common in people who have narcolepsy. Factors that can cause them include the following:

• Current drug use
• Past alcohol use
• Anxiety
• Mood disorders
• Insomnia

They can also be due to an epileptic seizure. In this case they tend to be brief, visual fragments.

Hypnagogic state symptoms

Hypnagogic state or hypnagogia, is a term that refers to sleep related hallucinations that occur during the transition from wakefulness to sleep (hypnagogic hallucinations) and from sleep to wakefulness (hypnopompic hallucinations) ¹. Visual, auditory and tactile sensations are most commonly reported (alone or co-occurring) ⁶. Individuals report hearing their name called just as they are falling asleep, feeling a presence in the room with them, seeing blurry images, noticing diffuse light, and having out-of-body experiences ³. Visual phenomena occur in 86% of all hypnagogia ⁷ typically consist of kaleidoscopically changing—possibly entoptic—phenomena such as geometric patterns, shapes and light flashes. Images involving animals, people and faces, and scenes also occur and are described as “lifelike,” highly detailed and colorful ⁸. Voices and other sounds (phone, doorbell, music) occur less commonly (8% to 34%) ⁹. They comprise vivid auditory impressions of words or names, people talking, and environmental or animal sounds ¹⁰. Somatic experiences also occur (25% to 44%) ², including bodily distortions, feelings of weightlessness, flying or falling, and a sense of presence in the room ¹¹.

You may have sleep hallucinations if you:

• Imagine events that seem very real just before falling asleep or just after waking up
• These imagined events are mainly visual

Hypnogogic hallucinations occur just before sleep, and may be accompanied by sleep paralysis, a state in which the subject is physically immobile, but fully conscious ²³. Hypnogogia and sleep paralysis often cause fear, moreso than in sleep paralysis during hypnopompia which is often considered as part a dream by the subject, as well as feelings of difficulty breathing and muscle tightness. Hypnopompia occurs upon waking, and may also be accompanied by sleep paralysis. Sleep paralysis is much more common in hypnopompia than in hypnogogia. Sleep paralysis is often confused by the person experiencing it as part of a lucid dream, which accounts for the high number of recalled dreams with elements of being frozen in place, or being unable to move. Common hypnopompic experiences include the sensation of falling and the feeling of a presence in the room.

Narcolepsy symptoms

Narcolepsy symptoms include excessive daytime sleepiness, sudden bouts of sleep regardless of the circumstance and sleep paralysis. According to the University of Maryland Medical Center, about two-thirds of people with the disorder also experience an abrupt, temporary loss of muscle control. The loss of muscle tone, which is referred to as cataplexy, may be triggered by intense emotions, such as anger, surprise or laughing.

Another possible symptom is unusually vivid dreams. The dreams occur either as the person is falling asleep or as they are waking up. What makes the dreams particularly frightening is since the person is in a semi-wake state, the dreams seem real.

Although most people may not be familiar with narcolepsy, the condition is not as rare as you might think. According to the National Institute of Neurological Disorders and Strokes, about one in every 3000 people in the United States have the condition, although it’s often underdiagnosed.

Symptoms tend to start in childhood or the teen years, but the disorder can also develop later in adulthood. It’s not surprising that the narcolepsy can interfere with daily activities and make work and school challenging. People with narcolepsy can also have additional sleep disorders, such as restless leg syndrome or sleep apnea, which creates even more problems sleeping.

Hypnagogic state diagnosis

You should see a sleep specialist if hallucinations cause you great anxiety or often disrupt your sleep. If you have them along with severe daytime sleepiness, then you may have narcolepsy. In this case, you should see a sleep specialist right away.

The doctor will need to know when the hallucinations began. He or she will want to know how often they occur and how long they last. The doctor will need to know your complete medical, psychiatric, and sleep history. The doctor will want to know if you are unusually sleepy or have any other sleep problems. Be sure to inform him or her of any past or present drug and medication use.

Also tell your doctor if you have ever had any other sleep disorder. Find out if you have any family members with sleep problems. It will also be helpful if you fill out a sleep diary for two weeks. The sleep diary will help the doctor see your sleeping patterns. This data gives the doctor clues about what is causing your problem and how to correct it.

Your doctor may have you do an overnight sleep study if your problem is severely disturbing your sleep. This study is called a polysomnogram. It charts your brain waves, heart beat, and breathing as you sleep. It also records how your arms and legs move. This study will help reveal if the hallucinations are related to any other sleep disorder.

If you tend to be very sleepy during the day, then your doctor may also have you do a daytime nap study. This is called a Multiple Sleep Latency Test (MSLT). The MSLT will measure how fast you fall asleep during the day. It will also show what kind of sleep you have when you take a nap. It will help to show if your hallucinations are a sign of narcolepsy.

Hypnagogic state treatment

Sleep hallucinations may not need treatment, as they often occur infrequently and do not affect sleep quality. They may be a sign of mental stress though, or if coupled with daytime sleepiness, even narcolepsy. If the hallucinations are causing fear or anxiety, or to validate its causes, you may want to talk to your doctor or a sleep specialist. When issues of mental stress are suspected, you may be advised to contact a therapist, or practice relaxation techniques before bedtime to help the mind shut down. It may also be advised to stay out of bed until feeling extremely tired, to avoid laying awake in bed and having the mind wander onto issues that may be causing you stress or anxiety. It has been shown in studies that the clearer a person’s mind is, the less likely they are to hallucinate, or even dream ⁸.

If the hallucinations are the result of medication, drug or alcohol use, it may be advised to refrain from their use, and you may need to change medications if this is the case.

Any suspected case of narcolepsy should be consulted with a sleep specialist, and an overnight sleep study performed to look into it further. Narcolepsy can be a debilitating disorder that can be treated.

Treatment of narcolepsy

Although there is currently no cure for narcolepsy, there are a few narcolepsy treatments. For example, medications may be prescribed to decrease symptoms, such as excessive sleepiness and cataplexy. Medications approved by the FDA to treat the disorder include modafinil and sodium oxybate. Lifestyle changes and behavior strategies to improve sleep quality are also recommended, such as:

• Regular exercise
• Maintaining a comfortable sleep environment
• Keeping to a regular sleep schedule
• Relaxing before bed
• Maintaining a healthy weight
• Avoiding caffeine a few hours before bed.

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