Hypnagogic hallucinations refer to bizarre sensory perceptions (usually visual) that are perceived during a presomnal state, or upon the transition from pre-sleep wakefulness to sleep.  These bizarre perceptions may be psychologically disturbing and extremely vivid.  Perhaps you’ve seen odd shapes with vivid colors, or especially odd imagery prior to falling asleep. In this case, your brain may have generated a “hypnagogic hallucination.”

The phenomenon of hypnagogic hallucinations was first reported informally in 1664 by Isbrand Van Diemerbroeck, a Dutch physician.  He described a case of a 50-year old woman with sleep paralysis and comorbid hypnagogic hallucinations in which she believed she was being attacked by the devil.  Formalized reports of hypnagogic hallucinations began in the 1840s with a publication from Jules-Gabriel-Francois Baillarger, a French psychiatrist.

Experiencing hypnagogic hallucinations is relatively common among those with sleep disorders (e.g. narcolepsy), mental illnesses (e.g. schizophrenia), and generalized insomnia.  Even among the general population, it is estimated that approximately 37% of individuals will experience hypnagogic hallucinations on the brink of sleep onset.  Various altered states of consciousness such as those exhibited during: lucid dreaming, out-of-body experiences, and sleep paralysis – may be closely related to hypnagogic hallucinations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/18691361

What are hypnagogic hallucinations? Definition.

Hypnagogic: This is a term that is a combination of the Greek word “hypnos” which means “sleep” and the word “agōgos” which translates to “leading.”  Upon combining these words, we are left with a single term that signifies leading or preceding (agōgos) falling asleep (hypnos).  It was coined in the 1800s by Alfred Maury to define the state of consciousness upon sleep onset.

Hallucinations: This is a term that refers to perceptual experiences that have no basis in reality.  In other words, a hallucination is an apparent (sensory) perception of something that isn’t present.

Hypnagogic hallucinations: Combining the terms hypnagogic (immediately before falling asleep) and hallucinations (perceptions that have no basis in reality), allows for easy understanding of the term hypnagogic hallucinations.  Hypnagogic hallucinations refer to perceptual experiences with no basis in reality, that occur during the consciousness of sleep onset.

  • Note: It is important to distinguish hypnagogic hallucinations (occurring during the transitory period between wakefulness and sleep) from “hypnopompic hallucinations” (occurring  during the transitory period of sleep to wakefulness).

What causes hypnagogic hallucinations?

It is difficult to pinpoint a universal cause for hypnagogic hallucinations, as the cause may be subject to significant individual variation.  In many cases, the neural activation and/or changes that occur to elicit the specific hallucinatory experience are likely to differ based on the person.  Someone with greater activation in the auditory centers of the brain may claim to hear a voice, while someone with heightened activation in the visual centers may claim to see geometric shapes.

Autosymbolism: A process called “autosymbolism” has been described as a hallucinatory experience that automatically represents whatever a person is thinking at the time.  This process was noted by the Vietnamese psychoanalyst, Herbert Silberer.  The concept of autosymbolism would suggest that hypnagogic hallucinations are a result of momentary thoughts or ideas.

These thoughts or ideas then manifest as a succinct image, sound, or other hallucination upon sleep onset.  One prominent example of autosymbolism was the discovery that the “benzene ring” was a closed structure. August Kekulé made this discovery during a reported hypnagogic state – involving imagery of molecules morphing into snakes.  Among these snakes, one happened to bite its tail, thus “closing the ring.”

Brain activity: Research demonstrates that there’s a correlation between neural activation of certain regions and hypnagogic hallucinations.  EEG activity appears to be altered prior to sleep in that an individual is increasingly responsive to sound.  This idea comes from a book published in 1987 called “Hypnagogia” by Andreas Mavromatis.

During episodes of hypnagogic hallucinations, it is known that the brain waves (EEG activity) changes and certain brain regions shut down.  There is likely an interaction between brain waves, REM-like frequencies, and regional activity, particularly in the parahippocampal region – which may result in hypnagogic hallucinations.

Brain waves: During hypnagogic hallucinations, it is believed that brain waves transition from fast-paced, high frequency waves to slower-paced, low frequency waves.  In other words, a person is transitioning from beta waves to alpha waves.  Think of this as shifting from the fastest gear on a manual transmission (beta) to the next slowest gear (alpha).

Studies show that hypnagogic phenomena may be a result of alpha waves transitioning to a “spindling” EEG.  A spindling EEG is characterized as bursts of beta waves (lasting less than a second), with predominantly slow wave activity.  These spindles are generated from the thalamus region of the brain.

Other researchers found that hypnagogic imagery is most likely to occur during sleep onset stages 4 and 5 as defined by Hori.  Stage 4 is characterized by a flattening of the EEG, while Stage 5 consists of rippled theta waves.  There are various techniques that have been used to prolong hypnagogic states such as: brainwave entrainment and neurofeedback.  If a person wants to extend the hypnagogic hallucinatory state, they’ll typically increase theta frequencies.

  • Source: http://psycnet.apa.org/psycinfo/1965-13652-001
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/17838964
  • Source: http://psycnet.apa.org/journals/drm/5/2/75/

Consciousness: The hallucinations occurring during a hypnagogic period are thought to be a result of both conscious and subconscious processes.  Covert REM activity may trigger an image or graphic related to something that you’ve been thinking about (conscious) or something that you’ve long forgot about (subconscious).  Your hallucinatory experience could even be a blending of both conscious and subconscious material.

During the hypnagogic state, we become increasingly suggestible, are likely to think illogical thoughts, and we’re more receptive to subconscious stimuli.  Some believe that our ego-fueled thoughts stop and we may experience a more relaxed, empathetic state of consciousness.

  • Source: http://www.jstor.org/discover/10.2307/2247720

Covert REM (Rapid Eye Movement):  It appears as though there’s a small (covert) emergence of REM (rapid-eye movement) that likely occurs during hypnagogic states.  Among some individuals, this rapid-eye movement may be the direct cause of their hypnagogic hallucinations, particularly those that claim to see vivid imagery.  Researchers found that REM-esque activity (from 1.5 to 3.0 Hz) in the parahippocampal region during presomnal states.

Upon sleep onset, the wakefulness promoting areas of the brain turn off, which may trigger the onset of the REM-esque activity in the parahippocampus.  This may then lead to an inhibition of the hippocampus, which could elicit hypnagogic phenomena like hallucinations.  Although a person isn’t considered to be in “REM,” the regional activity in the parahippocampus resembles a REM state, and the waves are within the “sawtooth” range.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/15763184
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/778884
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/18395615

Illicit drugs: One hypothesis to explain the appearance of hypnagogic hallucinations is that of a psychobiochemical disturbance (or abnormal neurotransmission).  This disturbance may be induced as a result of using an illicit drug – particularly one with hallucinogenic and/or stimulatory properties.  Those that abuse illicit drugs may exhibit various types of hallucinations during drug-induced psychosis.

Long-term usage or abuse of certain illicit substances may lead to structural, genetic, and neurotransmitter changes within the brain – increasing susceptibility to future hypnagogic hallucinations.  It should also be noted that during withdrawal from illicit drugs, a person’s brain and physiology may end up dealing with both acute and protracted adjustments in functionality, which could increase likelihood of hypnagogic phenomena.

Inconsistent sleep schedule: Those that work night shifts or have an inconsistent sleep schedule may be more prone to hypnagogic hallucinations prior to bed.  It is thought that neurotransmission, brain activity, hormones, and an array of other processes result from the body’s natural circadian rhythm.  When a person works a night shift and is constantly adjusting their sleep schedule, it results in neurophysiological chaos.

This is why many people end up with conditions like “shift work sleep disorder,” sleep paralysis, and inevitably hypnagogic hallucinations.  Those with highly variable or fluctuating sleep schedules may have a circadian rhythm disruption as a result of the inconsistency of sleep timing.  Adhering to a strict sleep schedule can reset the circadian rhythm and decrease likelihood of hypnagogic hallucinations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/22033666

Meditation: Those that frequently meditate may unexpectedly experience hypnagogic hallucinations.  While different types of meditation affect the brain leave unique neural imprints based on the specific practice, some researchers believe that meditation can prolong the hypnagogic state.  In other words, you could theoretically use a meditative practice to deliberately extend and/or explore hypnagogic states.

Similar practices such as neurofeedback, brainwave entrainment, and neural stimulation may allow an individual to prolong the hypnagogic state and/or increase likelihood of hallucinations.  Author James H. Austin believes that Zen meditation practitioners are capable of “freezing” hypnagogic states.  It is known that most types of meditation increase the strength of slower brain waves (e.g. alpha and theta), therefore it seems logical to think that hypnagogic hallucinations could be psychologically primed and/or prolonged.

  • Source: http://mitpress.mit.edu/books/zen-and-brain

Memory: Research comparing fully-formed images with fleeting images during hypnagogic states found neural distinctions based on the type of image perceived.  It is thought that external stimuli, preceding thoughts, and imagery-related memories play a role in influencing what a person sees.  Additionally, various types of memory including: immediate, short-term, medium-term, and long-term are all thought to influence imagery formation during hypnagogic states.

Semantic memory: During the hypnagogic state, it is thought that individuals are increasingly prone to forgetfulness.  The hippocampus becomes impaired, leading to poorer autobiographical and episodic memory.  However, despite impaired hippocampal functioning, semantic memory is still processed.

Semantic memory is considered a portion of long-term memory related to processing of concepts and ideas that are distinct from individual experiences.  Without access to autobiographical and episodic forms of memory, but an access to semantic memory, we may see things that are common: knowledge, colors, sounds, or other “facts” we’ve accumulated throughout our lifetime.

Neurotransmitters & receptors: It should be considered that among those who frequently experience hypnagogic hallucinations may differ in terms of neurotransmission, neurotransmitter levels, and receptor densities – possibly in the entire brain or specific regions.  It is highly likely that among those with specific mental illnesses, neurological conditions, or substance abusers – the altered neurotransmission may be responsible for causing the hypnagogic hallucinations.

It is known that those with abnormal neurotransmission of dopamine and glutamate are more prone to certain conditions like schizophrenia which are commonly associated with hallucinations.  There may be an increased likelihood for those with mental illnesses (particularly those in which hallucinations are a common symptom) to exhibit hypnagogic hallucinations.

It is thought that among those who abuse substances, neurotransmitter levels may be subject to sensitivity and depletion.  Furthermore, hypnagogic phenomena may occur as a drug-induced side effect, as an acute withdrawal symptom, or they may manifest as long-term effects.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12505794

Pharmaceutical drugs: If you are taking any pharmaceutical drug that affects neurotransmission, you may experience hypnagogic hallucinations as a result.  Some common examples of drugs that could provoke hypnagogic hallucinations include: antidepressants, antipsychotics, benzodiazepines, opioids, psychostimulants (ADHD medications), sleeping pills (Z-drugs).  The degree of vividness and specific type of hallucination may be related to the particular drug’s mechanism of action and/or the dosage.

Obviously if you’re taking more than one pharmaceutical drug that could affect brain activity, there may be an increased chance of experiencing drug-induced hypnagogic hallucinations.  Several cases of those using the drug Amitriptyline (a highly-popularized tricyclic antidepressant) have noted hypnagogic hallucinations.  In all cases, the individuals reported visual hallucinations and recognized that they were not real.

In particular, drugs that carry anticholinergic properties may increase odds of experiencing complex visual hypnagogic hallucinations.  It is believed that imbalances between serotonin and acetylcholine processes may also be responsible for triggering hypnagogic hallucinations.  Specifically, hyperactivity of serotonin systems with simultaneous hypoactivation of cholinergic processes could be what produces this effect.

It should be noted that if you are taking an antidepressant, hypnagogic hallucinations may ensue as a result of hyperactive serotonin systems or high serotonin levels.  Many drugs elicit secondary and tertiary effects as well, resulting in a possible cascade effect, which alters an individual’s entire neurochemistry.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/7468295
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/15495200

Pineal DMT: Due to the fact that hypnagogic hallucinations have been associated with paranormal phenomena, some have speculated that the brain releases DMT (dimethyltryptamine) via the pineal gland.  It is known that drugs triggering the release of DMT are associated with dream-like, hallucinogenic phenomena.  In his book DMT: The Spirit Molecule, Rick Strassman highlights the administration of DMT to a girl experiencing sleep paralysis with hypnagogic hallucinations.

Sensory deprivation: If you engage in sensory deprivation, you may increase your likelihood of experiencing hypnagogic phenomena, including hallucinations.  Those that use floatation tanks or restrict all senses – especially sight and sound – may temporarily alter brain functioning or produce an altered state of consciousness.  When senses are restricted, the brain is thought to fill in the gaps of deficient visual or auditory stimuli with hallucinations – such as seeing shapes, colors, or hearing sounds.

In particular, if you engage in sensory deprivation prior to sleep onset, you may notice hypnagogic hallucinations.  Just realize that it’s your brain’s way of compensating for a lack of stimuli or “filling in the sensory gaps.”

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/13780969

Sleep deprivation: Those that are sleep deprived may experience hypnagogic hallucinations throughout the day.  When a person hasn’t gotten enough sleep, a person naturally becomes tired, brain activity shifts, and neurotransmitter concentrations change.  Chronic sleep deprivation or restriction makes a person prone to fall asleep at randomized times throughout the day.

Hypnagogic hallucinations may be reported prior to a nap or even unexpectedly as a person falls asleep.  Chronic sleep restriction or excess deprivation can impact the circadian rhythm, and result in a variety of sleep problems and phenomena, including hallucinatory hypnagogia.

  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3564638/

Sleep position: Those that sleep in the “supine position” (on their backs) may be more likely to experience hypnagogic hallucinations than those sleeping in other positions.  Multiple studies analyzing individuals with narcolepsy discovered that nearly 80% of all reported hallucinatory experiences during sleep occurred in the supine position.  Researchers believe that various brain functions are directly related to sleep posture.

Among those experiencing nightmarish sleep paralysis hallucinations, sleeping in the back position can be a contributing factor.  Should a person want to stop sleep paralysis and possibly prevent hypnagogic hallucinations, altering sleep position from the “supine” posture to sleeping on the side (or even the stomach) may be recommended.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/18691361

Supplements: Any supplements that alter your neurotransmission (e.g. 5-HTP to enhance serotonin) may result in hypnagogic hallucinations prior to bed.  If you’re taking a supplement and notice you’re seeing odd visuals before bed and/or hearing weird sounds right before you fall asleep, it may be a result of your supplementation.  Even sleep supplements like melatonin could result in hypnagogic hallucinations.

Conditions that may cause hypnagogic hallucinations

There are many conditions that are thought to provoke hypnagogic hallucinations.  In each of these conditions, the underlying neural mechanisms responsible for the hypnagogic phenomenon may be subject to variation.  Those abusing certain drugs may experience the hallucinations as a result of neurotransmission alterations, while those who have seizures may experience them as a result of specific electrical activity (EEG).

Brain damage: Individuals that have endured various forms of brain damage are thought to be increasingly prone to hallucinations.  Brain damage may result in connectivity deficits between regions involved in sensory processing, leading a person to hallucinate.  Reports of brain lesions have highlighted the fact that inflicted damage can result in various types of hallucinations since the 1980s.

It seems as though the specific area as well as size of the lesion influence the corresponding hallucinations.  In the case of brain damage in the form of lesions, the brain may exhibit different activity during the transition from wakefulness to sleep, leading to hallucinations.  One theory is that lesions to certain parts of the brain allow dream mechanisms (geniculo-occipital spikes system) to break free from control of raphe nuceli (in the brainstem), resulting in hypnagogic hallucinations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/3629075

Epilepsy: There have been case reports of individuals experiencing hypnagogic hallucinations as a result of psychomotor seizures.  One particular case involved a woman who endured an automobile accident in her late 20s, followed by a head injury months after the event.  That said, she had no history of any psychiatric conditions.

As a 72 year old, she began complaining of seeing “black and white” visions prior to falling asleep.  These visions were recurrent in that they were reported between 5 and 6 nights each week.  In this particular case, the visions only lasted seconds and didn’t involve any other senses.  Upon careful analysis of this patient, doctors determined that she was diagnosed with psychomotor seizures in the past.

Her seizures were responsible for producing the hypnagogic hallucinations, which were viewed as a form of “epileptic discharge.”  This case demonstrates that among those that experience seizures and/or have been diagnosed with epilepsy, hypnagogic hallucinations may occur as a result.  The hypnagogic phenomena as produced by seizures tend to subside with proper medication for epilepsy.

  • Source: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1296002/

Learning disabilities: One study discovered that children with learning disabilities experience hypnagogic hallucinations at a greater rate than those of normal learning abilities. A study consisting of 180 children between ages 6 and 12 years found that approximately 35% of those with learning disabilities experienced hypnagogic hallucinations, whereas only 4% of those without learning disabilities experienced them.  This suggests that brain anatomy, activation, and brainwave patterns may be responsible.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12717648

Mental illness: Individuals with a mental illness such as schizophrenia, depression with psychotic features, bipolar disorder, etc. – may experience hypnagogic hallucinations more than usual.  Since many cases of hypnagogic hallucinations are likely a result of neurochemical alterations within the brain, those with mental illnesses may be increasingly susceptible to these phenomena.  Additionally how the hypnagogic hallucinations are interpreted (e.g. positive, neutral, or negative) may be related to the psychological state as induced by the specific disease.

Furthermore, it should be noted that many individuals with mental illnesses use illicit substances and/or take pharmaceutical drugs as a therapeutic means of treating their condition.  In any regard, these physiologically-foreign substances significantly alter neural processes, chemical concentrations, etc. – potentially resulting in hypnagogic hallucinations.

Neurodegenerative diseases: Those with neurodegenerative diseases are known to experience alterations in brain anatomy, receptor density, and neurotransmitter concentrations as a result of both their condition and possible medications that they may be taking.  Various conditions like Parkinson’s may be medicated with dopaminergic agents, resulting in hallucinatory experiences, some of which may occur during hypnagogic states.

It should be considered that hypnagogic hallucinations may be directly related to abnormalities in the brain or possibly be a mere reaction to the pharmaceutical agent that they take on a daily basis.

Sleep disorders: If you have a sleep disorder, you are significantly more likely to experience hypnagogic hallucinations.  Specifically, it has been found that among those diagnosed with narcolepsy, hypnagogic hallucinations are relatively common.  That said, it is believed that hypnopompic hallucinations (those experienced between states of sleep and wakefulness) are more common among those with narcolepsy.

In many cases, those with sleep disorders are falsely misdiagnosed with psychotic symptoms, when in reality they’re experiencing hypnagogic hallucinations.  For this reason, it is important to conduct a thorough evaluation to prevent misdiagnosing sleep disordered individuals with psychosis.  The hypnagogic hallucinations can be distinguished from psychotic halucinations based on their features.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/12956834
  • Source: http://www.ncbi.nlm.nih.gov/pubmed/8894197

Stress: Prolonged stress of any kind may increase susceptibility of experiencing hypnagogic hallucinations.  Stress, particularly over an extended period leads to alterations in our hormones, neurotransmitters, and the way our brain works.  In many cases, stress also disrupts the circadian rhythm, and increases likelihood of experiencing insomnia.

Research has shown that adults with high stress have a greater likelihood of “general sleep-related experiences” (GREs).  These GREs include the following: nightmares, falling dreams, and hypnagogic hallucinations.  In some cases, decreasing stress levels by increasing parasympathetic activation may lead to less GREs, including hypnagogic hallucinations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/21443286

Trauma: Those that have endured a traumatic experience are naturally less likely to get quality sleep.  Trauma is typically associated with prolonged stress, an increase in sympathetic nervous system activation (fight-or-flight), and the endogenous production of stimulatory agents like cortisol, norepinephrine, and dopamine.  A combination of stress, poor sleep quality, and neurochemical changes as a result of the trauma or unresolved PTSD could induce hypnagogic hallucinations.

  • Source: http://www.ncbi.nlm.nih.gov/pubmed/11086154

Note: For some people it may be that one specific factor causes hypnagogic hallucinations, while for others it may be a combination of several factor such as: sleep deprivation, chronic stress, and illicit drug abuse.

Types of Hypnagogic Hallucinations

During the transitory phase from wakefulness to sleep, a variety of hypnagogic phenomena have been reported.  Hallucinations experience during a hypnagogic state are most often visual, but may be auditory, tactile, or even olfactory.  In most reports of hypnagogic hallucinations, the duration may be short (a few seconds) or modest (a few minutes).

Visual (Imagery)

The most common type of hypnagogic hallucination is that of visuals or imagery.  This imagery may be related to something that you’ve been working on or thinking about for a prolonged period of time (e.g. the Tetris-effect), or it may be totally unpredictable drivel shuttled forth by your subconscious.  There are many hypotheses that attempt to explain the mechanisms that produce visual hypnagogic hallucinations.

  • Brain structure: Some experts believe that they may be caused by a disturbance or abnormality of brain structure.
  • Neurotransmitters: Others suggest that neurotransmission becomes temporarily disturbed, and produces hypnagogic hallucinations.
  • Psychodynamics: Another theory is that material from the unconscious or subconscious gets pushed into consciousness.
  • Combination: It has also been thought that a combination or interplay between structure, neurotransmission, and unconscious material may influence these hallucinations.

Visual hallucinations may be difficult to perceive as subtle images, or they may be extremely vivid.  The most common type of visual hypnagogic hallucination is including phosphenes, or the perception of light, despite no actual light source.  These little pseudo light particles may appear as geometrical shapes, specks, lines, outlines, dots, or a combination of several.  Additionally, they may appear completely flat, colored, moving, or 3-D.

Examples:

  • Blurred images
  • Dots
  • Geometrical shapes
  • Outlines
  • People
  • Specks of light
  • Symbols

Some people have reported experiences during which they claim to perceive a “tunnel of light.”  In this case, it seems as if their entire visual field is like a train moving through a completely lit tunnel.  It should be noted that most reports of visual hypnagogic hallucinations are subject to significant individual variation, and may be rapidly changing in terms of shape, size, color, and dimension.

In some cases a phenomenon known as the “Tetris effect” may influence the hypnagogic visuals.  This refers to individuals engaged in a repetitive visual activity prior to sleep that dominates their brain’s visual processing centers.  When the person gets drowsy, they may claim to see the same visuals of the repetitive visual activity (e.g. playing Tetris) as a hypnagogic hallucination (e.g. colored blocks from the game that appear to be moving).

Auditory (Sounds)

Perhaps the second most common type of hypnagogic hallucination is that of hearing sounds.  These sounds may be perceived as extremely faint, moderate, or loud to the point that they’re considered disturbing.  Some people may report hearing voices, animal sounds, a knock on the door, someone walking, or loud “booms” or “bangs.”  In the book “Hypnagogia” by Andreas Mavromatis, it is suggested that imagined speech is common in the form of fragments or speech related to the individual’s thoughts.

So if you were to hear a voice prior to falling asleep, there’s a chance that it could be reading your thoughts aloud.  In many cases the auditory hallucinations make no conscious or logical sense.  In some cases, a person may claim to hear music or the television playing, even after it has been turned off.

Examples:

  • Animal sounds
  • Buzzing
  • Humming
  • Loud noises
  • Music
  • Television
  • Voices
  • Walking
  • Whistling

Some have theorized that certain sounds such as animal sounds, buzzing, or humming may be directly related to the condition known as sleep paralysis.  This is characterized by REM (rapid-eye movement) occurring while a person is semi or fully conscious.  This leads to conscious perceptions of dream-related material.  The aforementioned “Tetris effect” may elicit an auditory effect for some individuals.

Tactile (Touch)

Perhaps the third most common type of hypnagogic hallucination is that of touch.  Many people claim to feel spiders crawling on their body prior to sleep, a soothing massage, pressure, or even painful sensations.  Tactile hypnagogic hallucinations may be a result of REM-induced atonia (lack of voluntary muscle control), or they may be a result of tactile stimuli experienced earlier in the day.

Examples:

  • Bodily pressure
  • Crawling sensations
  • Pain sensations
  • Rubbing
  • Tapping
  • Tickling

Olfactory (Smells)

While less common, some people report hallucinatory smells during hypnagogic states.  These smells may be pleasant, such as delicious foods, or may be unpleasant, such as rotten flesh.  In some cases the smell may be completely neutral such as that of fresh air.

Examples:

  • Delicious food
  • Fresh air
  • Rotten flesh
  • Smoke

Other hypnagogic hallucinations

Other examples of hypnagogic phenomena include: vestibular-motor or proprioceptive hallucinations, and gustatory (taste) hallucinations.

  • Vestibular-motor: Some people may experience proprioceptive hallucinations during a hypnagogic state.  They may feel as if their body is falling, rocking back and forth, floating, or moving at a fast pace.  These sensations are commonly associated with both sleep paralysis and out-of-body experiences.
  • Gustatory: A relatively uncommon hypnagogic hallucination is that of taste.  Some people may claim to experience a flash of taste such as that of a food or even something odd like a metallic item or leather.

Note: A person may experience one particular type of hypnagogic hallucination or multiple types (e.g. auditory and visual). The most common types are thought to be: visual, auditory, and tactile – in that order.  Additionally, secondary proprioceptive effects are thought to occur on occasion.

Hypnagogic Hallucinations Treatment

Although for many people hypnagogic hallucinations occur on an infrequent basis and aren’t bothersome, for others they may be disturbing.  In fact, they may be disturbing enough to interfere with both sleep quality and quantity.  Due to the sheer variation in potential causes for hypnagogic hallucinations, the treatment for one person’s hypnagogic hallucinations may differ significantly from that of another.

  • Antipsychotics: If a person has a severe mental illness such as schizophrenia or depression with psychotic features, they may benefit from an antipsychotic to control the neurotransmission of dopamine.  It is possible that among these individuals, chaotic firing of dopamine may contribute to and/or enhance various hypnagogic hallucinations.  While psychotic hallucinations tend to differ from standard hypnagogic hallucinations, there may be some overlap in patients diagnosed with mental illnesses.
  • Avoid drugs & alcohol: If you’re a heavy drinker or are using drugs on a frequent basis, chances are that they may interfere with your sleep quality and/or brain’s ability to transition into a sleeping state.  Common examples of substances that you may want to avoid include: nicotine, alcohol, and even caffeine – especially in the afternoon.  If you’re a substance abuser and know that the drugs cause these hypnagogic hallucinations – stop using and remain abstinent.
  • Brainwave alterations: In some cases, an intervention using targeted neurofeedback or brainwave entrainment may promote a healthier transition from wakefulness to sleep, resulting in less overall hypnagogic hallucinations.  If you work with sleep experts, they should be able to pinpoint specific brainwave changes on an EEG that are contributing to these phenomena.  Through a targeted brainwave training protocol, you may be able to reduce the occurrence of hallucinatory hypnagogia.
  • Drug discontinuation: Obviously if you’re using certain pharmaceutical drugs that you believe may be directly causing your hypnagogic hallucinations, you may want to consider discontinuation and/or a dosage alteration.  It is known that certain medications, particularly tricyclic antidepressants (e.g. Amitriptyline) can cause hypnagogic hallucinations.  If these become disturbing, report them to your doctor and pursue alternatives.
  • Improve sleep (quality + quantity): The best thing a person can do for themselves to stop hypnagogic hallucinations is to improve both sleep quality and quantity.  This means setting a strict sleep schedule, sleeping in accordance with your body’s natural circadian rhythm, and getting enough total sleep for restorative effects.  Improving your sleep takes time and should eventually counteract the effects of sleep deprivation.
  • Sleep disorder treatment: If you have a sleep disorder or suspect that you have a sleep disorder, seek professional treatment from a sleep expert.  Various sleep disorders like narcolepsy are increasingly prone to experience these hypnagogic hallucinations.  With proper treatment for sleep disorders, a normative sleep cycle can be restored and hypnagogic phenomena tend to subside.
  • Stress reduction: If you are highly stressed or have suffered from some sort of trauma, you may need to reduce your stress.  This means taking time for a relaxing activity for at least 5, 10, or 15 minutes per day.  The goal should be to increase activation of the parasympathetic nervous system and tone down the sympathetic dominance.  Those that experience hypnagogic hallucinations as a result of stress may want to consider using a tool called the emWave2.
  • Supplements: If you want, you could experiment with supplements to determine whether they improve your sleep quality.  Examples of some common supplements people take to help with sleep include: melatonin, valerian root, and 5-HTP.  Keep in mind though that some supplements for sleep (e.g. 5-HTP) may increase incidences of hypnagogic hallucinations for some people.
  • Treat underlying medical conditions: If you have an underlying medical condition, especially one that is neurological, it is important to seek proper treatment.  Treating various conditions like neurodegenerative diseases (e.g. Parkinson’s), epilepsy, bipolar disorder, tumors, etc. – should help reduce hypnagogic hallucinations.  Without proper treatment, brain processes may stay altered, resulting in continuous or increasingly problematic hypnagogic hallucinations.

Coping with hypnagogic hallucinations

If you experience hypnagogic hallucinations it’s important to avoid panicking, as panic can provoke a fear-response.  It may be natural to freak out if you hear someone’s voice or see a weird shape, especially if you’re somewhat of a hypochondriac, but panic may further hamper your sleep quality.

Acceptance: Many people see hypnagogic phenomena and try to resist whatever they’re seeing.  If they see shapes or hear sounds, they may be cognizant of the fact that those shapes or sounds are hallucinatory, but they may not like the experience and try to resist it.  Resistance may enhance the hypnagogia, but in most cases, it’ll just send you into a state of further anxiety and panic related to sleep.

Try to accept whatever you experience and realize that it’s nothing more than your brain chemistry transitioning into sleep, during which you happened to see an odd shape.  Realize that the hypnagogic hallucinations aren’t considered dangerous or harmful.

Realization: It is also important to realize that hypnagogic hallucinations aren’t based in reality.  They aren’t real, rather they’re a sign that potentially abnormal activity is being generated within your brain.  Although they aren’t generally considered harmful, many people fail to realize this and panic – thinking that something is severely wrong with them.

Sleep journal: Another common sense thing to do is to keep a sleep journal.  Make note of how you felt before going to bed, after waking up, and any hypnagogic hallucinations that you experienced.  You may want to note how much sleep you got, whether you went to bed at a reasonable time, and track any other variables that may have caused or improved your hypnagogic hallucinations.

Therapy: If you aren’t able to cope with the hypnagogic hallucinations and want some professional advice, you may want to seek out the help of an experienced therapist.  There are many different types of therapy that you may benefit from, including psychoanalytic therapy, which focuses on unconscious processes that may manifest during the wakefulness to sleep transition.

Frequently Asked Questions (FAQs)

Below are a few common questions associated with hypnagogic hallucinations.  If you have another question that you’d like answered, feel free to post it in the comments section below.

How long do hypnagogic hallucinations last?

In most cases, hypnagogic hallucinations may last anywhere from milliseconds to a few minutes.  For a majority of people they’ll last seconds or be a brief “flash in the pan” – whereas for others they may persist for awhile longer.  The ones that tend to last several minutes may be a result of the Tetris effect, substance usage, or psychiatric conditions (e.g. schizophrenia).  It is possible to experience even longer hypnagogic hallucinations than several minutes – but these aren’t commonly reported.

Do the hypnagogic hallucinations have a special meaning?

The hypnagogic hallucinations have whatever meaning you assign to them.  They aren’t special messages from a deity, spirits, or other souls – rather they are a result of your brain activity.  You may find that they are related to a particular activity that you had been engaged in during the previous day or a topic that your brain had been fixated upon for awhile prior to sleep.

Some people do interpret these hypnagogic hallucinations as being spiritual visions, prophecies, premonitions, apparitions, and other forms of inspiration.  Let’s realize that some discoveries (e.g. benzene molecule shape) have been made as a result of hypnagogic hallucinations.  Therefore in some cases, it may be your brain’s way of regurgitating, processing, and projecting information (or a problem) that you’ve been pondering.

Are hynpagogic hallucinations good or bad?

From a scientific perspective, these hallucinations shouldn’t be considered “good” or “bad” – they are a neutral phenomena.  However, for some individuals, they may be interpreted as a positive sign (good), or a detrimental omen (bad).  Usually interpretations are related to the content of the particular hallucination as well as the psychological state of the individual.

For example, if the hallucinatory content is a sense of tactile pain and the sight of a devilish figure – it will likely be interpreted as bad.  If the hallucinatory content is the smell of fresh muffins – it may be interpreted as good.  Additionally if the content is of a colorful geometric floating shape, it may be interpreted as neither good nor bad.

Have you ever experienced hypnagogic hallucinations?

If you’ve ever experienced hypnagogic hallucinations or had a hallucinatory experience immediately preceding the onset of sleep, feel free to share it in the comments section below.  To help others better understand your experience, mention the hallucinatory subtype(s) that you experienced (e.g. audio, visual, a combination) and whether you enjoyed the experience.  For some people the hypnagogic hallucinations are terrifying, for others they are pleasant, and for another group of people they are completely neutral.

You may also want to include what you believe caused the hypnagogic hallucinations such as a medical condition, drug, supplement, or poor sleep hygiene.  Understand that although they are most common among those with sleep disorders like narcolepsy, some research has reported that over 1/3 of the general population will experience them throughout their lifetime.