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How are hallucinations generated, is it related to dreaming?

How are hallucinations generated, is it related to dreaming?

I was thinking how powerful auditory and visual hallucinations must be, for the individual experiencing them to be unable to distinguish them from reality. I, personally, have not experienced a hallucination, but have experienced vivid dreams and know that when I'm dreaming it can seem real, and at that point, that is my reality (even though I am asleep).

Is there a correlation between the part of the brain responsible for dreaming and hallucinations?

What generates hallucinations, to make them indistinguishable from reality?


Psychosis results in hallucinations. States of psychosis are thought to be like seizures caused by imbalanced levels of at least dopamine and serotonin. Psychosis like depression creates new pathways in the brain which allow for the senses to be flooded with internal information. The person who is experiencing hallucinations may be forced by the psychosis to think that it is real. Some are able to realize that the hallucination is not real. For instance, it is a common condition of humanity to have isolated instances of hallucinations. People hear music when there is none or think someone calls their name but no one did. Normal people are able to recognize that there was no music and no one called their name.

Psychosis can be caused by extreme excitement. Excitement alone impairs judgment but if it goes to an extreme a person can become psychotic and begin to hallucinate or have other odd behaviour.

Often times people schizo type and bipolar disorder are accompanied with insomnia. If the illness progresses far enough the sick person can become caught in a state between awake and asleep. The hallucinations are combined with greater degrees of dissociation (day dream).


The short answer is "Yes" - there is a practice of taking conscious control of one's dreams called "Lucid Dreaming". This practice involves a number of techniques used to achieve awareness and control within a dream.

One of the techniques, called Wake Induced Lucid Dreaming (WILD) involves staying still in bed for extended periods of time. After a fairly long time (~45 minutes) the dreamer slips into a dream while being awake. The transition between waking state and dreaming state, when experienced consciously features numerous different types of hallucinations.

The phenomenon has been confirmed by a lot of people, the types of hallucinations most frequently described are: feeling "vibrations", hearing things, seeing things, feeling a presence of others in the room, falling through one's bed or being drawn out of the body. In most cases the dreamer is acutely aware that everything that is being felt is just a symptom of the WILD transition phase.

Because of the diversity of hallucinations experienced, I would conclude that dreaming and hallucinations are connected.


One way of describing it is that the brain is experiencing a case of non-shared deception. I say, "non-shared deception", for the following reasons…

People see cars stop, move, move faster, slow down, and stop again. However, a simple analysis of "motion", via the use of nothing but the mind, soon leads you to seeing the fact that all cars are constantly in motion, and that they never stop moving. This constant motion applies to all objects. All that can be done is change the direction of this constant motion as it is constantly on the go within a 4 dimensional structure known as Space-Time.

This simple ABC analysis of motion soon has you independently understanding Special Relativity, and it also has you independently, and successfully, creating all of the Special Relativity equations with absolute ease.

(To watch this easy breezy analysis of motion in action, goto youtube videos 1-9 at http://goo.gl/fz4R0I )

Thus, those who see objects, such as cars, speed up and slow down etc., are those whom are obviously "Seeing something that isn't really there.". They are experiencing an hallucination.

Now if the outward extension of the mind is reduced to an even smaller scale, via drugs or whatever, then the magnitude of the ongoing hallucinations are magnified even further, magnified to an even greater scale than the hallucinations that are being shared on a global scale.


Chemical factors

Hallucinations may be produced by chemical changes deriving from internal metabolic disturbances that are otherwise engendered inside of the body, or that originate from outside of the body. Some chemicals that produce hallucinatory experiences seem to act by reducing sensory input for example, dramatic hallucinatory recall of intense experiences from the recent past can be brought about by injections of anesthetic drugs such as sodium amobarbital, which favours the conditions for perceptual release. Hallucinations during induction of (and emergence from) general surgical anesthesia induced by a variety of other chemicals are well-known and can be explained on the same basis.

Such hallucinogenic chemicals seem to impair sensory input by decreasing the transmission of nerve impulses by raising the resistance of the nervous system to their passage. Other hallucinogens increase nerve transmission, disrupting the orderly input of information and “jamming the circuits.” Many botanically derived hallucinogens seem to function this way—e.g., LSD and the ergot (a fungus) that grows on rye, psilocybin from mushrooms, mescaline from the peyote cactus, and tetrahydrocannabinol (THC) from marijuana. Hallucinations also can be induced by input overload produced mechanically, such as bombarding several sensory systems with intense stimuli simultaneously (e.g., with bright flashing lights and loud noises).

Hallucinogenic drugs are substances that, administered in pharmacological doses (not toxic overdoses), create gross distortions in perception without causing loss of consciousness. These distortions frequently include hallucinations. Such compounds also are likely to exert profound effects on mood, thought, and observable behaviour. These resemble (or mimic) the disturbances generated in spontaneously occurring psychoses indeed some hallucinogens have been termed “psychotomimetic” or “psychotogenic” on this account.

Research scientists and clinicians such as psychiatrists have sometimes deliberately taken these compounds in efforts to understand how it feels to be a severely psychiatric patient. It has been hoped that the study of such chemically induced “model psychoses” would lead to improved methods of treatment. In addition, some psychiatric workers speak of “ psychedelic” (mind-manifesting) substances, controversially held to expand perceptual horizons and insight among a variety of people under treatment for such disorders as alcoholism, rigid personality patterns, and sexual frigidity.

The potentially dangerous psychological changes produced by psychedelic chemicals have sometimes been interpreted as “loosening ego structures,” “dissolving ego boundaries,” or “disrupting ego defenses.” Such changes may include the experiencing of thoughts, feelings, and perceptions that are usually outside the individual’s awareness (“unconscious” or “repressed”). Persons who take such drugs (e.g., LSD) may become hypersuggestible, emotionally unstable, and unusually aware of their own reactions and those of others. Feelings of transcendence of ordinary experience, distortions in time perception (e.g., time may seem to slow down), and hallucinations have also been reported.

It appears that all human behaviour and experience (normal as well as abnormal) is well attended by illusory and hallucinatory phenomena. While the relationship of these phenomena to mental illness has been well documented, their role in everyday life has perhaps not been considered enough. Greater understanding of illusions and hallucinations among normal people may provide explanations for experiences otherwise relegated to the uncanny, “extrasensory,” or supernatural. Such understanding may also illuminate the remarkable certainty that individuals express in their contrary interpretations of the same basic information. “Reality,” like beauty, lies in the eye of the beholder.


How are hallucinations generated, is it related to dreaming? - Psychology


Ramon A Boza, M.D.
Clinical Associate Professor, University of Miami
Consultant Psychiatrist, Miami Veterans Hospital

Hallucinations are defined as "an apparent perception of an external object when no such object is present" (1). It is to be differentiated from illusions in which real perceptions are misinterpreted. Although typically associated with psychiatric disorders, the hallucinatory experience has a wide range of etiologies that may include but is not limited to the following: neurological insult, seizure and sleep disorders, drug reactions, substance abuse, grief, stress, as well as metabolic, endocrine and infectious diseases.

  • I) Psychological Events (Non-Psychiatric conditions)
  • II) Use of Psychotomimetics and Medications side-effects.
  • III) Neurological and Sleep disorders
  • IV) Medico-Surgical conditions
  • V) Environmental and Industrial causes
  • VI) Pseudohallucinations

The term hallucination (from the Latin alucinari "to wander in mind") was introduced to the psychiatric literature by Esquirol in 1837. Hallucinations have been regarded as a restitutive symptom in Schizophrenia, as an attempt to make sense of a severe thought disorder. The American Psychiatric Association, Diagnostic Statistic Manual (2) criterion for the diagnosis of Schizophrenia requires "prominent hallucinations throughout the day, voices [unrelated] to depression or elation, a running commentary on the person, and two or more voices conversing with each other". It is also found as a symptom frequently associated to the severity of other mental illnesses.

However, in this review we will not refer to psychiaric conditions “per se”, but to specific psychological circumstances, in which the illusory-hallucinatory phenomena may be present.

a) In states of Mourning and Stress, voices can provide a sense of calmness and assurance. Geronimo, (3) the Apache leader, while grieving the massacre of his family, heard the message "no gun will ever kill you". From that day on, he believed he could not die by a bullet, and his daring in battle may have been partially based, on that assumption.

b) Sensory Deprivation can account for hallucinatory phenomena. Solomon et al. (4) quote from numerous autobiographies of explorers describing these events, i.e. Slocum, in his solo trip around the world, was directed during a gale to the right course by a hallucinated pilot. Brainwashing as experienced by POWs, jailed dissidents in totalitarian states, or terrorists' hostages, may also experience auditory perceptual disturbances.

c) Sleep Deprivation, as seen in critical situations, use of psychostimulants, or political torture may evoke dream imagery with comforting visual hallucinations erupting into the waking state. REM (Rapid-Eye Movement) fragments of the paradoxical stage of sleep may also appear in mixed states of sleep deprivation, fatigue, and boredom as when driving for long periods of time ("highway hypnosis").

d) Acquired Deafness. Musical hallucinations have been reported in patients suffering from acquired deafness. Sacks (5) wrote of David Wright, the South African poet, deaf since age seven. He heard "phantasmal voices" only when someone spoke to him, and could see his face and gestures. It is conceivable that, the skilled, post-lingual deaf, automatically translate the lip- reading into an auditory hallucinated equivalent.

e) Phantom limbs has been defined as proprioceptive hallucination of a limb, or other part of the body, that has been excised. Though the patient is fully aware of the amputation, he still feels that part of the body appended, moving, pained, or with other unusual paresthetic sensations (6).

f) Flashbacks (Post Hallucinogenic Perceptual Disorders), were originally described by Cohen (7) as secondary to the widespread use of hallucinogens. They seldom appear after more than a year without drugs. He reported visual slowing in the perception of time. Flashbacks, visual as well as olfactory, have also been reported as associated with Post Traumatic Stress Disorders (PTSD). A veteran reported that certain smells, such as gasoline or smoke, could trigger vivid flashbacks of combat memories. During a recent natural disaster (Hurricane Andrew), some of our patients reported that the heat, cold food, and the sound of the "choppers" threw them into vivid visual and olfactory hallucinations, from their Vietnam experiences of twenty years earlier.

a) Psychedelic drugs: In 1938, Hoffman (8) synthesized a new compound he thought could have analeptic properties. Eventually, he carried out a self-experiment in which he ingested lysergic acid diethylamide (LSD) and reported: "[It] surged upon me an uninterrupted stream of fantastic [kaleidoscopic-like]images of extraordinary plasticity and vividness". He also noticed, the phenomena of synesthesias (receiving stimuli through a different sensory channel, such as seeing voices, or hearing colors), and trailing (moving objects are seen as a series of discrete and discontinuous images similar to stroboscopic photography or discotheque light effects).

Phencyclidine (PCP), as well as peyote, mescal, psilocybin, and, rarely, cannabis, tetrahydrocannabinol (THC), and the "phenylethylamine designer drugs", (3-4-methylene-dioxy- methamphetamine, (Ecstasy) 3-5 methylene-dioxy-etamphetamine (Eve), ("Ice"), methamphetamine consumed through smoking can generate bizarre, colorful visions with peculiar forms such as lattice, grating, or spirals. Artists and aesthetes of the “fin de siecle” such as Poe, Coleridge, de Quincey, Baudelaire and Gauthier, used hashish and opiates as means to increase their visual imagery and artistic creativity.

b) Prescriptions and Over the Counter Medications (OTC)

Some of the pharmacological agents that might generate hallucinations are the following: Alpha-adrenergic agonist anti- hypertensives like clonidine the anti-parkinsonian agents such as bromocriptine, selegiline, and carbidopa the anti-convulsant carbamazepine analgesics like pentazocine and fentanyl and anti-vertigo drugs like diphenidol. Also the psychotropic agents with robust anti-cholinergic effects, as well as the serotonin re-uptake blocker antidepressants (SSRI). The histamine-2 blocker used in the treatment of peptic ulcer disease are also capable of generating hallucinations. Antiarrhythmic agents, such as tonocaide, may be hallucinogenic in close to 12 % of patients.

Finally, dronabinol, an antiemetic cannabinoid used in the treatment of nausea associated with chemotherapy, can generate hallucinations in up to 5 % of cases (9).

a) Chromatopsias are illusions in which the environment is seen as uniformly tinted with a color. Xanthopsias (yellow vision) have been reported with Digitalis use (10), and purple vision may be seen with Santonin, an anti-helminthic (11).

b) Size hallucinations: Lilliputians are real hallucinations in which the patients see imaginary people of a small size, usually associated with pleasant feelings. Brodnignagian hallucinations, are just the opposite, people may be seen as giants.

c) Metamorphosias, are visual illusions (12). They may include the following: Dysmegalopsia, (alterations in the form of objects), micropsia and macropsia in which real visual perceptions are seen smaller or larger than they really are. Micropsia can be accompanied by teleopsia, in which the minified object is seen far away. In pelopsia objects are seen as getting closer. Allesthesia modifies the perception of the place where a true object really is. Palinopsia, is a persistent visual sensation after the object has been removed from the patient's visual field. These events have more an illusory than hallucinatory quality, and are frequently associated with either parietal lobe pathology or as a component of a migrainous aura.

2).- Tactile (haptic), proprioceptive, somatic, and visceral hallucinations.

Drug related: Formicative hallucinations are tactile phenomena found with the abuse of Alcohol, Methylphenidate, Amphetamines, and Steroids. The patients complain of "bugs" crawling in their skin, and may vigorously scratch themselves. Some of the most severe, chronic cases have been successfully treated with the neuroleptic pimozide (13). Use of Amyl nitrate (14) as an inhalant may arouse erotic sensations in the genital area. It has also been used to evoke a sense of prolonged orgasmic pleasure.

a) Epilepsy. Abnormal electric activity in diverse brain localizations may elicit hallucinatory phenomena of a peculiar nature. Alajouanine (15) quotes from Dostoyevsky's experience of an auditory aura and a sense of Epiphany: "The air was filled with a big noise and I thought it had engulfed me. I have really touched God. [No one] can imagine the happiness [epileptics] feel the second before our fit. Mahomet, in the Koran, said he has seen the Paradise. I don't know if this felicity lasts for seconds, hours or months, but, for all the joys life brings, I would not exchange this one".

Penrose and Wilder (16) reported many kinds of sensory seizures, such as feelings of numbness, tingling, heat, or water running in patients with centro-parietal foci. Abnormal electric hallucinations. Occipital cortical discharges can generate elementary visual hallucinations such as light spots, twirling objects, and geometrical figures. Etiology may include, traumatic cortical scars, post-concussion syndrome, neoplasms, infarctions, vascular malformations, lupus erythematous, degenerative, vasculitic lesions, or metabolic insult.

Olfactory, or uncinate seizures, are mostly reported as unpleasant odors, such as burning rubber, feces, rotting manure, sulfur, or indescribable. Frequently, the olfactory hallucinations are associated with aural gustatory hallucinations. The patient may describe elementary tastes like sweet, salty, bitter, or odd flavors.

Gustatory hallucinations are seldom found as an early sign of cognitive derrangement. One of our veterans, began to complain of having a bad taste in his mouth. Eventually, he believed that a pocket of poison has been implanted in his teeth by his dentist, and that he could bite himself and die. Further decline and clinical evolution pointed toward early manifestations of Alzheimer's Dementia. Patients suffering from psychotic depression may also, report the illusion of bad taste in their mouth (17).

Peduncular hallucinations: They originate from lesions of the mid-brain tegmentum. They may be elaborated and complex, rich in color, and depict landscapes, familiar faces, buildings, or lilliputian visions. Feeling tone may be absent, and the patient witnesses them with calm amusement.

Auditory and Vertiginous Hallucinations:
1.- Auditory: Stimuli of the transverse gyrus of Heschl of the temporal lobe, may elicit auditory events. Sacks (18) quotes on Dimitri Shostakovich, the Soviet composer, who reportedly had a metallic shell fragment in the temporal horn of his left ventricle. He said "since the fragment has been there, each time [I lean] my head to one side, I can hear music - different each time!" Apparently he would use this method while composing, producing melodic models for his symphonies.

2.- Vertiginous: Meniere's disease is the cause of severe kinesthetic hallucinations , accompanied by nausea, dizziness, and malaise. It may be also have tinnitus, often described as "chirping", or as the sound of crickets. This must be clinically differentiated from acoustic neuroma, vertebro-basilar artery syndromes, and other posterior fossa entities.

Autoscopic hallucinations: These are a blend of visual and proprioceptive hallucinations. Lhermitte has defined them as "the visual hallucination of the self" (19). In these cases, the vision is of one's double, like in a mirror, sometimes repeating one's gestures, and on occasions busy with other activities, a veritable doppelg„nger (6). They may be secondary to hypnopompic hallucinations, migraine, seizure disorders, delirium, encephalitis, post-concussion syndrome, or even non-neurological events such as: transcendental meditation, mystic events, use of hallucinogens, and near death experiences.

Sleep Disorders. Have shown a variety of perceptual disturbances.

1.-Narcolepsy-Cataplexy (Gelineau): Aldrich (20) has reviewed the syndrome and reports the symptomatology of hypnagogic hallucinations (before falling asleep), sleep paralysis, and cataplexy sometimes triggered by a strong emotion or during a laughing attack. He believes these phenomena are a dissociated manifestation of REM Sleep, with an increased excitability of the giant cells of the pontine-reticular formation that allow visions to intrude into wakefulness.

Mellman and co-authors (21) reported two PTSD patients who experienced sleep disturbances and recurrent daytime hallucinations. Further studies confirm these patients suffered from narcolepsy as well. They assert that the content of PTSD symptoms and narcolepsy tended to dissociate, and that the PTSD symptomatology remitted while narcolepsy persisted and progressed.

Hypnopompic hallucinations: Siegel (22) reports once being overwhelmed by a very vivid hypnopompic vision (when waking up). He had a "sense of pressure in his chest from a being, talking in reverse, rendering him unable to move". He compares the experience, to the ones reported in medieval religious literature as a succubus, (a she-devil), versus incubus (a he- devil).

Variant Angina. A 67 year old WWII veteran had a repeated hypnopompic vision of his platoon fighting toward a Japanese machine-gun nest. At the end of his dream, he had been shot in the chest and experienced a tearing, excruciating pain. He would wake up with tachycardia, cold sweats, and a sense of impending doom. After further cardiovascular evaluation, including challenge tests, he was diagnosed as having a Prinzmetal variant angina. This coincides with other clinical observations of ischemic episodes while awakening from nightmares (23).

Sleep Apnea: Another veteran, (24) seen by us had repeated complaints of mild memory impairment, restless sleep, loud snoring and sleep paralysis. He had a repetitive frightening hallucinations of a dead former girlfriend, "with a long gown, a dagger in her hand, and transparent like smoke". He experienced substantial improvement of his Sleep Apnea after being placed on protriptyline, losing 40 pounds, and having an uvulo-palato-pharyngoplasty and adeno-tonsillectomy.

Migraine attacks can be the cause of a variety of perceptual distortions. Most frequently though, the so called, "fortification spectra" hallucinations (teichopsia) are seen. They may show as irregular, colored, shimmering, edged, scintillating crescents, developing close to the center of the visual field. Sacks (18) believes that the visions of St. Hildegarde, a 12th century mystic, were typical migrainous hallucinations. Patients with classic migraine (25) suffer from perfusion changes either in the retina or in the visual pathway. Therefore, hallucinations of various geometric shapes, zigzag, or turrets can be seen. Rarely migraine can produce an upside-down vision of an observed object.

The Alice in Wonderland syndrome has been recently reported (26). It involves hallucinatory feelings of change in the body image. One migrainous patient reported " I get all tired out from pulling my head down. [It feels] like a balloon, my neck stretches and my head goes up to the ceiling". LSD users and children suffering from Epstein-Barr virus infection have reported similar symptoms.

Experimental stimulation of the cortex: Penfield (27), while operating on epileptic patients at the Montreal Neurological Institute (MNI), stimulated various areas of the cortex. These were cooperative, fully conscious patients during the neurosurgical procedure, and could give accurate descriptions. He was able to elicit vivid imagery of what appear to have been previous, trivial life events. In the operating room, patients reported voices of friends, songs heard long ago, or pleasant, nostalgic reveries of youthful gatherings. He postulated that "somewhere in the brain of each of us there is a continuous ongoing record of the stream of consciousness, from birth to death" (28).

Rarely, some medical entities such as diabetes mellitus, multiple sclerosis, serous otitis media and intra-otic foreign bodies can generate unusual sounds, clicks, murmurs, roars, humming, buzzing or whizzing as was reported by Coleman back in 1894 (29).

a) Entoptic hallucinations are related to lesions or abnormalities somewhere within the visuo-neural pathways. Roberts (11) has mentioned the post-cataract surgery delirium called "Black Patch disease". New surgical techniques have made its occurrence obsolete. Recently Holroyd et al (30) reported visual hallucinations in patients with macular degeneration with the associated risk factors of living alone, history of stroke and bilateral worsening of visual acuity. This points to a dual etiology of sensory deprivation, and decreased cortical inhibition.

b) Charles Bonnet's syndrome is a clinical entity of the elderly, first described by the Swiss naturalist, as an account of the visual hallucinations experienced by his grandfather. He described them as "amusing and magical visions, coexisting with reason" (31). It is now defined as a persistent recurrent visual hallucinatory phenomenon of a pleasant nature, with a clear state of consciousness, compelling, but seen by the patient as unreal. It is associated with ocular pathology, and tends to be "remarkably crisp and detailed, and at times lilliputian".

Some veterans who were under continuous enemy fire, or who served in heavy artillery units complain of permanent bilateral noises, and tinnitus. The frequent exposure to high decibel sounds as in heavy metal rock bands, percussion instruments, and jackhammers may produce persistent noises once the stimulus has ceased. The incessant rattle of a train's wheels may eventually sound like rhythmic, illusory, repetitive phrases.

Mirages are visual illusions such as those seen while driving and seeing wet pavement at a distance. They are due to a combination of individual factors and the reflection of light through different densities of heated air. Continuous work with computer and TV monitors may bring flickering in the visual fields.

They have been defined as hallucinations that the patient knows to be such (1). Although the perception is rather vivid and crisp, the patient has the insight that it has no external foundation. Therefore, its primary characteristic is the awareness of the unreality of the hallucinatory experience. The cases with obtunded sensorium portend a worse prognosis.

a) Radio-reception. A 35 year old Vietnam combat, veteran (32) started to complain of depression, headaches, and hearing blurred voices and music. Skull X-rays showed shrapnel metallic densities in the soft tissues and cranial bones of the left parieto-occipital region. His perception of voices and music were matched with stations in the AM broadcast band, and consistently identified the same station in the 560 Khz range. His radio- reception involved the metal implant diode rectification of the radio signal, and its bone transmission to the auditory apparatus. Other cases of broadcast reception due to dental work have been reported as well.

b) Virtual reality. A contemporary equivalent of the psychedelic culture has emerged with the use of "high-tech" interactive electronic gadgetry. These self-induced illusions of an alternate, parallel world may seem authentic and propel a compelling imagery. There is a potential for dependency in these pseudo-hallucinatory experiences of cyberspace.

Hallucinations and illusions, are part of a continuum of perceptual disturbances with manifold variations. They may entail idiosyncratic forms of bodily communication, or transfer of information from within or without. In the context of mental illness they are supported by thought disorder and crystallized delusional system. In states of delirium, drug intoxications, or neurological dysfunction, they may be perceived as transient, bewildering, unreal phenomena.

For the proper clinical management of a hallucinating patient, it is of the utmost importance to rule out a medical or neurological entity, perhaps an adverse drug reaction or use of hallucinogens within the context of a culturally validated phenomena. A psychiatric diagnosis should only be arrived at after a judicious evaluation of the phenomenology of the hallucinatory phenomena, circumstances in which they appear, and concomitant symptoms. In some instances, a psychiatric consultation may be in order.

1.- Hinsie L and Campbell R. Psychiatric Dictionary. Fourth Edition, Oxford University Press. New York, 1970.

2.- American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, American Psychiatric Association Press. page 113, Washington DC, 1987.

3 .-Roberts, D. Geronimo. National Geographic. 182: 46-71, October 1992.

4.- Solomon PH, Leiderman HE, Mendelson JA et al. Sensory Deprivation: A Review. Am. J. Psychiatry. 114: 357-363, 1957.

5.- Sacks OL. Seeing Voices: A Journey intro the world of the deaf, page 7, Univ. of California Press. Los Angeles, 1989.

6.- Boza RA, Milanes FE, Hanna GS and Trujillo MO. Psychiatric symptoms associated to Parietal Lobe Dysfunctions. Resident & Staff Physician. 39 (1):59-68, January 1993.

7.- Cohen, SI. Flashbacks. Drug Abuse & Alcoholism Newsletter. 6: No. 9, November 1977.

8.- Hoffman AL. The Discovery of LSD and subsequent investigations on naturally occurring hallucinogens. - Discovery in Biological Psychiatry -. page 91, Ayd FR & Blackwell BA, Eds. J.B. Lippincott Co. Philadelphia, 1970.

9.- Sifton DA and Mehta MU. PDR's Drugs Interactions and Side Effects System. Computer Database. Medical Economics Data. Release 3.1. Update September 1992.

10.-Lessell SI. Visual hallucinations and related phenomena. Weekly Update: Neurology and Neurosurgery. 2 (6): 48-54. Biomedia. Princeton, New Jersey, February 1980.

11.-Roberts JE. Differential Diagnosis in Neuropsychiatry. Chapter 16, Disorders of Perception, pages 258-271, J. Wiley & Sons. New York, 1986.

12- MacDonald, Critchley: "The Parietal Lobes." London. Hafner Press, 1953.

13.-Johnson GE and Anton RA. Delusions of parasitosis: differential diagnosis and treatment. Southern Medical Journal. 78 (8): 914-918, August 1985.

14.-Sigell LE, Kappa FR, Fusaro GR, et al. Popping and snorting volatile nitrites: A current fad for getting high. Am. J. Psychiatry. 135 (1): 1216-1218, Oct 1978.

15.-Alajouanine, T. Dostoiewsky's Epilepsy. Brain 86: 209-218 June 1963.

16.-Penrose RI and Wilder JO. Epilepsy: The Seizure - Variations on a Theme. pages 30-32. Neurology Series. F.A. Davis Co. Philadelphia, 1968.

17.-Carter JE. Visual, Somatosensory, Olfactory and Gustatory Hallucinations. The Interface of Psychiatry and Neurology. Psychiatric Clin. of N. America. 15 (2): 347-358, June 1992.

18.-Sacks, OL. The Man who mistook his Wife for a Hat: Chapter 15. Reminiscence, page 134, Chapter 20. The visions of Hildegard, page 160. Summit Books, New York, 1985.

19.-Lhermitte, JE. Visual hallucinations of the self. British Medical Journal. 1:431-434, March 3, 1951.

20.-Aldrich MI. Review Article: Narcolepsy. NEJM. 323 (6): 389-394. August 9, 1990.

21.-Mellman TO, Ramsay EU, and Fitzgerald ST. Divergence of PTSD and Narcolepsy associated with military trauma. Journal of Anxiety Disorders. 5:267-272, 1991.

22.-Siegel RO. Fire in the Brain: Clinical Tales of Hallucinations. Penguin Books. New York, 1992.

23.-Otsuka KO, Yanaga TA and Watanabe HA. Variant Angina and REM Sleep. American Heart Journal. 115: 1343-1345. June 1988.

24.-Boza RA, Trujillo MO, Millares SY, et al. Sleep Apnea and associated neuropsychiatric symptoms: A case report. VA Practitioner 1 (8):43-45, August 1984.

25.-Selby, GE. Migraine and its Variants. In Current Diagnoses - 5 Ed., page 961. Conn HO and Conn RE. W.B. Saunders & Co. Philadelphia, 1977.

26.-Rolak LO. Literary neurologic symptoms: Alice in Wonderland. Arch. Neurology. 48 (6): 649-651, June 1991.

27.-Penfield WI and Jasper HE. Epilepsy and the functional anatomy of the human brain, pages 453-461. Little Brown Co. Boston, 1954.

28.-Milner BR. In Memory Mechanisms. From Wilder Penfield: His Legacy to Neurology. Canadian Med. Journal. 116: 1365-1377, 1977.

29.-Colman WS. Hallucinations in the sane associated with local organic disease of the sensory organs. British Med. Journal 1 (1894): 1015-1017. May 12, 1894.

30.-Holroyd S, Rabins P, Finkelstein D, et al. Visual hallucinations in patients with macular degeneration. Am. J. Psychiatry. 149 (12): 1701-1706, December, 1992.

31.-Gold KE and Rabinds PE. Isolated Visual Hallucinations and the Charles Bonnet Syndrome: A Review of the Literature and Presentation of Six Cases. Comp. Psychiatry 30 (1): 90-98, January/February 1989.

32.-Boza RA and Liggett ST. Pseudohallucinations: Radio-reception through shrapnel fragments. Am. J Psychiatry. 138 (9): 1263-1264, September 1981.


Hallucinations Seen as Another Troubling COVID-19 Symptom

by Stacey Colino, AARP, October 6, 2020 | Comments: 0

En español | Jamie Colvin-Choate thought she was tied to a bed while bugs crawled over her, that she heard her friends plotting against her, and that, at 65, she'd just had a baby — all while hospitalized for a severe COVID-19 infection last summer.

Colvin-Choate nearly died twice, had a tracheotomy and a feeding tube inserted, and was put into a medically induced coma. But she counts the hallucinations she suffered, and “having to decipher what was real and what wasn't after I came through,” as the hardest part of her ordeal.

For the latest coronavirus news and advice go to AARP.org/coronavirus.

When Drew Murrie, hospitalized for COVID-19, woke up in the ICU last spring, he remembered vivid images of being stuck in a cave stacked with skeletons, of electric butterflies flying around the room and, at one terrifying moment, of a human hand covering his face while he was in bed. “I had never had visions like this before,” says Murrie, 59, who lives with his family in the Chicago suburbs. “I had no idea what was going on.”

According to a recent review of studies in Psychology Research and Behavior Management, COVID-19 infections have been triggering such hallucinations, as well as things like delusions and paranoia in patients with no history of mental health issues. Such temporary symptoms of psychosis have become yet another surprising effect the virus has on the brain. In some patients, hallucinations may be part of the delirium that accompanies a long COVID-19 illness or hospital stay in others, these visions can occur on their own. A study released this week and conducted at the Northwestern Medicine health system showed that up to one-third of hospitalized patients showed “altered mental function,” a term that includes things like delusions, as well as confusion and unresponsiveness. (Unlike hallucinations, however, these neurological symptoms can have a long-term impact.)

It's not fully understood why this happens, but one idea is that patients with severe COVID-19 infection “may have a little brain damage from chronically low levels of oxygen going to the brain, due to COVID causing the lungs not to oxygenate the blood as well,” explains Pravin George, a staff neurointensivist at Cleveland Clinic. “It could also be that COVID itself is attacking the brain directly in certain patients.”

The disease caused by the virus may also trigger inflammation in areas of the brain that could cause symptoms like hallucinations. And powerful medications, such as steroids, which are used to reduce inflammation could also be a cause in some, notes psychiatrist Stephen Ferrando, M.D., director and chair of the Department of Psychiatry at Westchester Medical Center in Valhalla, New York. The body's response to inflammation could also contribute, he adds, since “the immune cascade or cytokine storm behind COVID may play a role in triggering a variety of mental health problems.”

In some patients, hallucinations — which can be as subtle as detecting a burnt-rubber smell when none exists — precede hospitalization and can be a red flag for doctors. “When people present with hallucinations or delusions in the ER, we now test for COVID,” Fernando says.

Such was the case with Marilyn Schneider, 57, who spiked a 104.5 fever in late March. To stay on top of what she needed to do while feeling ill, she posted notes around her home, reminding her to wake up her son at a certain hour for school and to feed the dog and let him out. (Her dog had died six years earlier and her 24-year-old son is in graduate school.)

"I was in a twilight zone while my fever was high,” recalls Schneider, an executive secretary at the Cleveland Clinic Fairview Hospital. “I never had hallucinations before — I don't even dream — so this was very odd for me.” When she rolled over in bed and saw an image of herself pleading for help, she called 911 and ended up in the hospital ICU. That vision may have saved her life.


The Ancient, Peaceful Art of Self-Generated Hallucination

Cornelia Kopp via Flickr

A fter five years of practicing meditation, subject number 99003 began to see the lights. “My eyes were closed,” he reported, “[and] there would be what appeared to be a moon-shaped object in my consciousness directly above me, about the same size as the moon if you lay down on the ground and look into the night sky. It was white. When I let go I was totally enveloped inside this light… I was seeing colors and lights and all kinds of things going on… Blue, purple, red. They were globes they were kind of like Christmas-tree lights hanging out in space, except they were round.”

Subject 99003 described these experiences to Jared Lindahl, a researcher from Warren Wilson College in Asheville, North Carolina, who has spent years scientifically studying meditation. He and his team are the midst of a large study on meditators and their experiences, and in a recent paper they homed in on a peculiar experience many of them share: mysterious lights that appear in their mind’s eyes as they practice.

To figure out just where these lights might be coming from, Lindahl and his team talked to 28 meditators for an average of 77 minutes each. Nine of them reported “light experiences,” with descriptions much like subject 99003’s. “Sometimes there were, oftentimes, just a white spot, sometimes multiple white spots,” one said. “Sometimes the spots, or ‘little stars’ as I called them, would float together in a wave, like a group of birds migrating, but I would just let those things come and go.”

Another said: “In concentration I’ve had rays of white light that go through everything. They’re either coming from behind me somewhere or coming out of the object that I was concentrating on… I saw it with my eyes open and it wasn’t really seeing it was something else, even though I still was perceiving that I was there.”

Buddhist literature refers to lights and visions in myriad ways. The Theravada tradition refers to nimitta, an vision of a series of lights seen during meditation that can be taken to represent everything from the meditator’s pure mind to a visual symbol of a real object. In one Buddhist text, called The Path of Purification, the nimitta is described this way:

It appears to some as a star or cluster of gems or a cluster of pearls, […] to others like a long braid string or a wreath of flowers or a puff of smoke, to others like a stretched-out cobweb or a film of cloud or a lotus flower or a chariot wheel or the moon’s disk or the sun’s disk.

Other Buddhist traditions also refer to lights during meditation, but Lindahl points out in the paper that “there is no single, consistent interpretation of meditation-induced light experiences in Buddhist traditions.” And yet the appearance of lights isn’t a fluke occurrence—it’s something that many meditators experience, and that many traditions have tried to incorporate and explain.

“Sometimes the spots, or ‘little stars’ as I called them, would float together in a wave, like a group of birds migrating, but I would just let those things come and go.”

So where are these lights coming from? They’re clearly not real, physical lights dancing in front of the meditator’s face, but rather a construction of the idle, meditating brain. What is it about meditation that opens the brain up to these kinds of hallucinations?

To answer that question, Lindahl and his team looked for occasions where the descriptions he gathered from meditators intersected with descriptions of neurophysiological disorders. They found that both the first-person accounts and the Buddhist literary descriptions of these lights intersected pretty well with the experiences of people undergoing the intentional practice of sensory deprivation.

Hallucinations are relatively well-documented in the world of sensory deprivation, and they dovetail with the lights seen by meditators. Where meditators describe jewel lights, white spots and little stars, those under sensory deprivation sometimes describe dots and points of light. Where meditators see shimmering ropes, electrical sparks, and rays of light that go through everything, the sensory deprived might see visual snow, bright sunsets, and shimmering, luminous fog. Neuroscientists think that when the eyes and ears are deprived of input, the brain becomes hypersensitive and neurons may fire with little provocation, creating these kinds of light shows. Lindahl suspects that the lights that meditators see are the result of the same phenomenon—that meditating is itself a mild form of sensory deprivation.

In some ways, this is not surprising. Meditation often involves being alone, in a quiet, dimly lit room. Some Tibetan Buddhists practice what’s called “mun mtshams,” or “dark retreat,” in which they close themselves off in the dark. And it’s not just about the physical spaces where meditation happens—many forms of meditation are focused on isolating a single stimulus and shutting out everything else, a kind of mental sensory deprivation. By focusing on breath, a specific vision, a single object, or something else as they get into the zone, meditators are “guarding the sense doors” from the rest of the world. This may be an ancient trick for creating a space of intentional sensory deprivation and opening oneself up to the dazzling light show that often follows.


Examples of Delusions

Any persistent and false belief may be a delusion, but as with hallucinations there are some common types and categories of delusions, most often triggered by a mental illness or psychotic episode:

  • Persecutory. These are delusions in which a person believes someone is out to get them or is mistreating them.
  • Grandiose. A grandiose delusion is any belief relating to having special powers, relationships with someone important or famous, or having exceptional talents or abilities.
  • Jealous. Delusions of jealousy involve believing a partner is being unfaithful.
  • Somatic. A false belief that one is sick or physically disabled is somatic.
  • Bizarre. Delusions are often non-bizarre, meaning they could be true but aren’t. Bizarre delusions are those that could not be true, such as believing someone is controlling one’s mind.

Vivid dreams or bizarre dreams that stay with you

Vivid dreams may arise for a variety of reasons. They may indicate you are suffering from certain medical conditions, which might include neurodegenerative disorders like Parkinson's disease. There are other, less frightening reasons for your weird dreams as well, so don't jump to conclusions too quickly.

This may come as a surprise to you, but particularly bizarre or memorable dreams might also indicate a possible infection. "Any infection increases the amount of slow-wave sleep we have, however, this delays the starting point of when we enter dreaming sleep, so dreaming sleep starts late, and can erupt into consciousness. This leads to vivid dreams and strange hallucinations," Dr. Patrick McNamara, a neurologist from Boston University Medical School, told the International Business Times.

Alcohol can also prompt vivid and memorable dreams. This is because the effects of alcohol wear off toward morning, affecting your brain chemicals and triggering bizarre and sometimes scary dreams.

Like alcohol, medications like antidepressants can also trigger vivid dreams, said Dr Patrick McNamara of the Boston University Medical School. "They've been shown to make REM bursts more intense in the people who take them," says Deirdre Barrett, Ph.D., assistant clinical professor of psychiatry at Harvard Medical School in Boston and author of The Committee of Sleep. "And most of those people seem to have more nightmares as a side effect." If your medications are interfering with your sleep and your dreams, discuss them with your doctor. It might be time to switch medications.


Sleep Apnea Linked To Sleepwalking, Hallucinations And Other 'Parasomnias'

Nearly 1 in 10 patients with obstructive sleep apnea also experience "parasomnia" symptoms such as sleepwalking, hallucinations and acting out their dreams, a Loyola University Chicago Stritch School of Medicine study has found.

Researchers examined records of 537 adult sleep apnea patients who were evaluated at the Loyola Center for Sleep Disorders in Maywood and Oak Brook Terrace. Fifty-one patients, or 9.5 percent of the total, reported one or more types of parasomnia symptoms.

Parasomnia complaints included sleep paralysis (21 patients), sleep-related hallucinations (16 patients), acting out dreams (11 patients), sleepwalking (5 patients) and eating while asleep (one patient).

Results were reported at Sleep 2009, the annual meeting of the Associated Professional Sleep Societies, held this year in Seattle.

Obstructive sleep apnea is caused by a partial or complete blockage of the airway. Each time this happens, the brain becomes aroused, in order to resume breathing. This is disruptive to sleep, and the patient can feel chronically tired during the day.

Earlier studies found that obstructive sleep apnea is associated with a higher risk of high blood pressure, heart attacks, stroke, obesity, diabetes, heart failure and irregular heartbeats. The new study suggests that apnea also is linked to increased parasomnia symptoms.

Parasomnia disorders include sleep paralysis (brief episodes of being unable to move), hallucinations during the state between waking and sleeping, acting-out dreams (punching, kicking, crying out, etc.) and walking, eating or even driving while asleep.

Because it interrupts sleep, apnea can set a person up for parasomnia, said Dr. Nidhi S. Undevia, principal investigator of the study. "If you have a predisposition to parasomnia, apnea could make it worse," Undevia said. Undevia is medical director of the Loyola Center for Sleep Disorders and an assistant professor in the Department of Critical Care Medicine at Loyola University Chicago Stritch School of Medicine.

Undevia said doctors should ask apnea patients if they have parasomnia symptoms. "We need to start asking, because we might be missing potentially dangerous or harmful behaviors," she said.

Other co-authors are Loyola sleep specialist Dr. Sunita Kumar, an assistant professor in the Department of Critical Care Medicine at Stritch School of Medicine and lead author Dr. Mari Viola-Saltzman, a sleep medicine fellow at the University of Washington. During the course of the study, Viola-Saltzman was a neurology resident at Loyola University Hospital.

Viola-Saltzman said that, in addition to screening patients for snoring, apneic spells, disrupted sleep and daytime somnolence, physicians "may also consider asking about parasomnia symptoms as another tool to indicate whether the patient may be suffering from obstructive sleep apnea."

Story Source:

Materials provided by Loyola University Health System. Note: Content may be edited for style and length.


What are hypnagogic hallucinations?

Hypnagogic hallucinations are imagined sensations that seem very real. They occur as a person is falling asleep, and are also referred to as sleep hallucinations.

The term hypnopompic describes the period when a person wakes up. Hypnagogic defines the period when a person falls asleep.

A hallucination is anything that can be sensed but is not real. A hallucinated smell, taste, vision, or sound is only experienced in a person’s mind and not by others.

Hallucinations that occur around sleep have fascinated scientists, writers, and philosophers for many centuries. Research about their causes and link to dreams is ongoing.

Aside from narcolepsy, hypnagogic hallucinations may be caused by Parkinson’s disease or schizophrenia.

Sleepwalking, nightmares, sleep paralysis, and similar experiences are known as parasomnia. Often there is no known cause, but parasomnia can run in families.

A person will experience vivid hallucinations as they fall asleep, or just before falling asleep. These can be images, smells, tastes, tactile sensations, or sounds.

A person may also feel as if they are moving while their body is still.

This sensation could be a feeling of falling or flying.

Visual hallucinations

The most common hypnagogic hallucinations are visual. They may include images of people, animals, or moving objects.

Images can be quite complex and detailed, and may not make any sense.

Other symptoms

During a hypnagogic hallucination, a person knows that they are awake. The images, sounds, or other sensations may last a number of minutes. They may prevent a person from falling asleep.

These hallucinations may happen at the same time as sleep paralysis.

Difference from dreaming

The key difference between a dream and a hypnagogic hallucination is that the hallucination will feel very real. A person may feel sure that they have seen or felt something, and this can be frightening or confusing.

Certain factors may increase the likelihood of experiencing a hypnagogic hallucination.

They tend to occur less frequently as a person ages, and women are more likely to experience these hallucinations than men.

If a person uses drugs or alcohol, they may be more likely to experience hypnagogic hallucinations. The condition is also linked to anxiety and insomnia.

Hypnagogic hallucinations are not usually a risk to health.

Certain medical conditions are associated with these hallucinations. If a person has any of the following symptoms, they may wish to see a doctor.

  • Symptoms of narcolepsy: These include muscle weakness, being very sleepy during the day, and having a disturbed sleep at night.
  • Symptoms of schizophrenia: These include hearing voices, having confused thoughts, and experiencing changes in behavior.
  • Symptoms of Parkinson’s disease: These include slow movement, muscle stiffness, and shaking in the hands and other parts of the body.

A migraine may also lead a person to see colors, lights, or images that do not exist. These visualizations are called auras. They usually occur alongside a headache and are different from hallucinations.

Hypnagogic hallucinations can be very disturbing. They can stop a person from sleeping well, and cause stress or anxiety. If this is the case, a person may wish to see a doctor.

If a person feels that they can live with their hypnagogic hallucinations, they may not need treatment. If there is no underlying medical condition, changes to lifestyle may lessen the frequency of hallucinations.

Getting enough sleep and avoiding drugs and alcohol can reduce their frequency. If hypnagogic hallucinations cause disrupted sleep or anxiety, a doctor might prescribe medication.

When these hallucinations are not caused by an underlying condition, they usually do not have long-term complications. Their most common effects are disturbed sleep, and stress or anxiety.

However, hypnagogic hallucinations can cause a person to wake in terror and scream or shout, which may disturb a partner or roommate.

Also, a person experiencing a hallucination may fall out of bed or otherwise injure themselves.

Many of these issues can harm health and well-being. A person may wish to consult a doctor for advice or treatment.

During sleep, many parts of the brain are still active. Processes such as breathing and circulation are normal.

Most people will also dream, although not everyone can remember doing so. The reasons for dreaming are still not completely understood. It may be a way for the brain to sort through information or recall memories.

The body will cycle through periods of deeper and lighter sleep throughout the night. Dreaming and types of parasomnia, such as sleepwalking, mostly happen during deeper sleep.

As a person falls asleep or wakes up, they will usually enter a period of lighter sleep. Narcolepsy can cause a person to enter directly into a period of deeper sleep, or wake up in the middle of one. This may cause dreams or hallucinations to feel more real.

Scientists are not sure what causes hypnagogic hallucinations in people who do not have narcolepsy. It may happen for similar reasons, as periods of deeper and lighter sleep overlap.

Hypnagogic hallucinations tend to have no long-term side effects. They often happen because of an underlying medical condition or during periods of poor sleep and stress.

Getting advice and treatment for an underlying condition can help to reduce the frequency of hypnagogic hallucinations.

Making changes to a sleep schedule and getting more rest will often resolve the condition.


Repeated visual hallucinations in Parkinson's disease as disturbed external/internal perceptions: focused review and a new integrative model

Visual hallucinations (VH) in Parkinson's disease (PD) are a chronic complication in 30 to 60% of treated patients and have a multifaceted phenomenology. Flickering, faultive impressions, and illusionary misperceptions precede the core syndrome of stereotyped, colorful images. The patient variably recognizes these images as hallucinations, being rarely irritated or frightened and more often amused as a bystander. Although studies on VH in PD focus on several research domains, no comprehensive, unified theory has been developed to study their pathophysiology. We have adapted Hobson's work on the states of consciousness and propose a model integrating seemingly disparate data on VH. We suggest that VH should be considered as a dysregulation of the gating and filtering of external perception and internal image production. Contributive elements and anatomical links for the model include poor primary vision, reduced activation of primary visual cortex, aberrant activation of associative visual and frontal cortex, lack of suppression or spontaneous emergence of internally generated imagery through the ponto-geniculo-occipital system, intrusion of rapid eye movement dreaming imagery into wakefulness, errative changes of the brainstem filtering capacities through fluctuating vigilance, and medication-related overactivation of mesolimbic systems. Different etiologies likely produce different phenomenologies and the prognosis may not be uniform. This new conceptual framework permits an anatomical view of VH and suggests new, testable hypotheses regarding their pathophysiology and therapy.


Chemical factors

Hallucinations may be produced by chemical changes deriving from internal metabolic disturbances that are otherwise engendered inside of the body, or that originate from outside of the body. Some chemicals that produce hallucinatory experiences seem to act by reducing sensory input for example, dramatic hallucinatory recall of intense experiences from the recent past can be brought about by injections of anesthetic drugs such as sodium amobarbital, which favours the conditions for perceptual release. Hallucinations during induction of (and emergence from) general surgical anesthesia induced by a variety of other chemicals are well-known and can be explained on the same basis.

Such hallucinogenic chemicals seem to impair sensory input by decreasing the transmission of nerve impulses by raising the resistance of the nervous system to their passage. Other hallucinogens increase nerve transmission, disrupting the orderly input of information and “jamming the circuits.” Many botanically derived hallucinogens seem to function this way—e.g., LSD and the ergot (a fungus) that grows on rye, psilocybin from mushrooms, mescaline from the peyote cactus, and tetrahydrocannabinol (THC) from marijuana. Hallucinations also can be induced by input overload produced mechanically, such as bombarding several sensory systems with intense stimuli simultaneously (e.g., with bright flashing lights and loud noises).

Hallucinogenic drugs are substances that, administered in pharmacological doses (not toxic overdoses), create gross distortions in perception without causing loss of consciousness. These distortions frequently include hallucinations. Such compounds also are likely to exert profound effects on mood, thought, and observable behaviour. These resemble (or mimic) the disturbances generated in spontaneously occurring psychoses indeed some hallucinogens have been termed “psychotomimetic” or “psychotogenic” on this account.

Research scientists and clinicians such as psychiatrists have sometimes deliberately taken these compounds in efforts to understand how it feels to be a severely psychiatric patient. It has been hoped that the study of such chemically induced “model psychoses” would lead to improved methods of treatment. In addition, some psychiatric workers speak of “ psychedelic” (mind-manifesting) substances, controversially held to expand perceptual horizons and insight among a variety of people under treatment for such disorders as alcoholism, rigid personality patterns, and sexual frigidity.

The potentially dangerous psychological changes produced by psychedelic chemicals have sometimes been interpreted as “loosening ego structures,” “dissolving ego boundaries,” or “disrupting ego defenses.” Such changes may include the experiencing of thoughts, feelings, and perceptions that are usually outside the individual’s awareness (“unconscious” or “repressed”). Persons who take such drugs (e.g., LSD) may become hypersuggestible, emotionally unstable, and unusually aware of their own reactions and those of others. Feelings of transcendence of ordinary experience, distortions in time perception (e.g., time may seem to slow down), and hallucinations have also been reported.

It appears that all human behaviour and experience (normal as well as abnormal) is well attended by illusory and hallucinatory phenomena. While the relationship of these phenomena to mental illness has been well documented, their role in everyday life has perhaps not been considered enough. Greater understanding of illusions and hallucinations among normal people may provide explanations for experiences otherwise relegated to the uncanny, “extrasensory,” or supernatural. Such understanding may also illuminate the remarkable certainty that individuals express in their contrary interpretations of the same basic information. “Reality,” like beauty, lies in the eye of the beholder.


What are hypnagogic hallucinations?

Hypnagogic hallucinations are imagined sensations that seem very real. They occur as a person is falling asleep, and are also referred to as sleep hallucinations.

The term hypnopompic describes the period when a person wakes up. Hypnagogic defines the period when a person falls asleep.

A hallucination is anything that can be sensed but is not real. A hallucinated smell, taste, vision, or sound is only experienced in a person’s mind and not by others.

Hallucinations that occur around sleep have fascinated scientists, writers, and philosophers for many centuries. Research about their causes and link to dreams is ongoing.

Aside from narcolepsy, hypnagogic hallucinations may be caused by Parkinson’s disease or schizophrenia.

Sleepwalking, nightmares, sleep paralysis, and similar experiences are known as parasomnia. Often there is no known cause, but parasomnia can run in families.

A person will experience vivid hallucinations as they fall asleep, or just before falling asleep. These can be images, smells, tastes, tactile sensations, or sounds.

A person may also feel as if they are moving while their body is still.

This sensation could be a feeling of falling or flying.

Visual hallucinations

The most common hypnagogic hallucinations are visual. They may include images of people, animals, or moving objects.

Images can be quite complex and detailed, and may not make any sense.

Other symptoms

During a hypnagogic hallucination, a person knows that they are awake. The images, sounds, or other sensations may last a number of minutes. They may prevent a person from falling asleep.

These hallucinations may happen at the same time as sleep paralysis.

Difference from dreaming

The key difference between a dream and a hypnagogic hallucination is that the hallucination will feel very real. A person may feel sure that they have seen or felt something, and this can be frightening or confusing.

Certain factors may increase the likelihood of experiencing a hypnagogic hallucination.

They tend to occur less frequently as a person ages, and women are more likely to experience these hallucinations than men.

If a person uses drugs or alcohol, they may be more likely to experience hypnagogic hallucinations. The condition is also linked to anxiety and insomnia.

Hypnagogic hallucinations are not usually a risk to health.

Certain medical conditions are associated with these hallucinations. If a person has any of the following symptoms, they may wish to see a doctor.

  • Symptoms of narcolepsy: These include muscle weakness, being very sleepy during the day, and having a disturbed sleep at night.
  • Symptoms of schizophrenia: These include hearing voices, having confused thoughts, and experiencing changes in behavior.
  • Symptoms of Parkinson’s disease: These include slow movement, muscle stiffness, and shaking in the hands and other parts of the body.

A migraine may also lead a person to see colors, lights, or images that do not exist. These visualizations are called auras. They usually occur alongside a headache and are different from hallucinations.

Hypnagogic hallucinations can be very disturbing. They can stop a person from sleeping well, and cause stress or anxiety. If this is the case, a person may wish to see a doctor.

If a person feels that they can live with their hypnagogic hallucinations, they may not need treatment. If there is no underlying medical condition, changes to lifestyle may lessen the frequency of hallucinations.

Getting enough sleep and avoiding drugs and alcohol can reduce their frequency. If hypnagogic hallucinations cause disrupted sleep or anxiety, a doctor might prescribe medication.

When these hallucinations are not caused by an underlying condition, they usually do not have long-term complications. Their most common effects are disturbed sleep, and stress or anxiety.

However, hypnagogic hallucinations can cause a person to wake in terror and scream or shout, which may disturb a partner or roommate.

Also, a person experiencing a hallucination may fall out of bed or otherwise injure themselves.

Many of these issues can harm health and well-being. A person may wish to consult a doctor for advice or treatment.

During sleep, many parts of the brain are still active. Processes such as breathing and circulation are normal.

Most people will also dream, although not everyone can remember doing so. The reasons for dreaming are still not completely understood. It may be a way for the brain to sort through information or recall memories.

The body will cycle through periods of deeper and lighter sleep throughout the night. Dreaming and types of parasomnia, such as sleepwalking, mostly happen during deeper sleep.

As a person falls asleep or wakes up, they will usually enter a period of lighter sleep. Narcolepsy can cause a person to enter directly into a period of deeper sleep, or wake up in the middle of one. This may cause dreams or hallucinations to feel more real.

Scientists are not sure what causes hypnagogic hallucinations in people who do not have narcolepsy. It may happen for similar reasons, as periods of deeper and lighter sleep overlap.

Hypnagogic hallucinations tend to have no long-term side effects. They often happen because of an underlying medical condition or during periods of poor sleep and stress.

Getting advice and treatment for an underlying condition can help to reduce the frequency of hypnagogic hallucinations.

Making changes to a sleep schedule and getting more rest will often resolve the condition.


Repeated visual hallucinations in Parkinson's disease as disturbed external/internal perceptions: focused review and a new integrative model

Visual hallucinations (VH) in Parkinson's disease (PD) are a chronic complication in 30 to 60% of treated patients and have a multifaceted phenomenology. Flickering, faultive impressions, and illusionary misperceptions precede the core syndrome of stereotyped, colorful images. The patient variably recognizes these images as hallucinations, being rarely irritated or frightened and more often amused as a bystander. Although studies on VH in PD focus on several research domains, no comprehensive, unified theory has been developed to study their pathophysiology. We have adapted Hobson's work on the states of consciousness and propose a model integrating seemingly disparate data on VH. We suggest that VH should be considered as a dysregulation of the gating and filtering of external perception and internal image production. Contributive elements and anatomical links for the model include poor primary vision, reduced activation of primary visual cortex, aberrant activation of associative visual and frontal cortex, lack of suppression or spontaneous emergence of internally generated imagery through the ponto-geniculo-occipital system, intrusion of rapid eye movement dreaming imagery into wakefulness, errative changes of the brainstem filtering capacities through fluctuating vigilance, and medication-related overactivation of mesolimbic systems. Different etiologies likely produce different phenomenologies and the prognosis may not be uniform. This new conceptual framework permits an anatomical view of VH and suggests new, testable hypotheses regarding their pathophysiology and therapy.


Sleep Apnea Linked To Sleepwalking, Hallucinations And Other 'Parasomnias'

Nearly 1 in 10 patients with obstructive sleep apnea also experience "parasomnia" symptoms such as sleepwalking, hallucinations and acting out their dreams, a Loyola University Chicago Stritch School of Medicine study has found.

Researchers examined records of 537 adult sleep apnea patients who were evaluated at the Loyola Center for Sleep Disorders in Maywood and Oak Brook Terrace. Fifty-one patients, or 9.5 percent of the total, reported one or more types of parasomnia symptoms.

Parasomnia complaints included sleep paralysis (21 patients), sleep-related hallucinations (16 patients), acting out dreams (11 patients), sleepwalking (5 patients) and eating while asleep (one patient).

Results were reported at Sleep 2009, the annual meeting of the Associated Professional Sleep Societies, held this year in Seattle.

Obstructive sleep apnea is caused by a partial or complete blockage of the airway. Each time this happens, the brain becomes aroused, in order to resume breathing. This is disruptive to sleep, and the patient can feel chronically tired during the day.

Earlier studies found that obstructive sleep apnea is associated with a higher risk of high blood pressure, heart attacks, stroke, obesity, diabetes, heart failure and irregular heartbeats. The new study suggests that apnea also is linked to increased parasomnia symptoms.

Parasomnia disorders include sleep paralysis (brief episodes of being unable to move), hallucinations during the state between waking and sleeping, acting-out dreams (punching, kicking, crying out, etc.) and walking, eating or even driving while asleep.

Because it interrupts sleep, apnea can set a person up for parasomnia, said Dr. Nidhi S. Undevia, principal investigator of the study. "If you have a predisposition to parasomnia, apnea could make it worse," Undevia said. Undevia is medical director of the Loyola Center for Sleep Disorders and an assistant professor in the Department of Critical Care Medicine at Loyola University Chicago Stritch School of Medicine.

Undevia said doctors should ask apnea patients if they have parasomnia symptoms. "We need to start asking, because we might be missing potentially dangerous or harmful behaviors," she said.

Other co-authors are Loyola sleep specialist Dr. Sunita Kumar, an assistant professor in the Department of Critical Care Medicine at Stritch School of Medicine and lead author Dr. Mari Viola-Saltzman, a sleep medicine fellow at the University of Washington. During the course of the study, Viola-Saltzman was a neurology resident at Loyola University Hospital.

Viola-Saltzman said that, in addition to screening patients for snoring, apneic spells, disrupted sleep and daytime somnolence, physicians "may also consider asking about parasomnia symptoms as another tool to indicate whether the patient may be suffering from obstructive sleep apnea."

Story Source:

Materials provided by Loyola University Health System. Note: Content may be edited for style and length.


How are hallucinations generated, is it related to dreaming? - Psychology


Ramon A Boza, M.D.
Clinical Associate Professor, University of Miami
Consultant Psychiatrist, Miami Veterans Hospital

Hallucinations are defined as "an apparent perception of an external object when no such object is present" (1). It is to be differentiated from illusions in which real perceptions are misinterpreted. Although typically associated with psychiatric disorders, the hallucinatory experience has a wide range of etiologies that may include but is not limited to the following: neurological insult, seizure and sleep disorders, drug reactions, substance abuse, grief, stress, as well as metabolic, endocrine and infectious diseases.

  • I) Psychological Events (Non-Psychiatric conditions)
  • II) Use of Psychotomimetics and Medications side-effects.
  • III) Neurological and Sleep disorders
  • IV) Medico-Surgical conditions
  • V) Environmental and Industrial causes
  • VI) Pseudohallucinations

The term hallucination (from the Latin alucinari "to wander in mind") was introduced to the psychiatric literature by Esquirol in 1837. Hallucinations have been regarded as a restitutive symptom in Schizophrenia, as an attempt to make sense of a severe thought disorder. The American Psychiatric Association, Diagnostic Statistic Manual (2) criterion for the diagnosis of Schizophrenia requires "prominent hallucinations throughout the day, voices [unrelated] to depression or elation, a running commentary on the person, and two or more voices conversing with each other". It is also found as a symptom frequently associated to the severity of other mental illnesses.

However, in this review we will not refer to psychiaric conditions “per se”, but to specific psychological circumstances, in which the illusory-hallucinatory phenomena may be present.

a) In states of Mourning and Stress, voices can provide a sense of calmness and assurance. Geronimo, (3) the Apache leader, while grieving the massacre of his family, heard the message "no gun will ever kill you". From that day on, he believed he could not die by a bullet, and his daring in battle may have been partially based, on that assumption.

b) Sensory Deprivation can account for hallucinatory phenomena. Solomon et al. (4) quote from numerous autobiographies of explorers describing these events, i.e. Slocum, in his solo trip around the world, was directed during a gale to the right course by a hallucinated pilot. Brainwashing as experienced by POWs, jailed dissidents in totalitarian states, or terrorists' hostages, may also experience auditory perceptual disturbances.

c) Sleep Deprivation, as seen in critical situations, use of psychostimulants, or political torture may evoke dream imagery with comforting visual hallucinations erupting into the waking state. REM (Rapid-Eye Movement) fragments of the paradoxical stage of sleep may also appear in mixed states of sleep deprivation, fatigue, and boredom as when driving for long periods of time ("highway hypnosis").

d) Acquired Deafness. Musical hallucinations have been reported in patients suffering from acquired deafness. Sacks (5) wrote of David Wright, the South African poet, deaf since age seven. He heard "phantasmal voices" only when someone spoke to him, and could see his face and gestures. It is conceivable that, the skilled, post-lingual deaf, automatically translate the lip- reading into an auditory hallucinated equivalent.

e) Phantom limbs has been defined as proprioceptive hallucination of a limb, or other part of the body, that has been excised. Though the patient is fully aware of the amputation, he still feels that part of the body appended, moving, pained, or with other unusual paresthetic sensations (6).

f) Flashbacks (Post Hallucinogenic Perceptual Disorders), were originally described by Cohen (7) as secondary to the widespread use of hallucinogens. They seldom appear after more than a year without drugs. He reported visual slowing in the perception of time. Flashbacks, visual as well as olfactory, have also been reported as associated with Post Traumatic Stress Disorders (PTSD). A veteran reported that certain smells, such as gasoline or smoke, could trigger vivid flashbacks of combat memories. During a recent natural disaster (Hurricane Andrew), some of our patients reported that the heat, cold food, and the sound of the "choppers" threw them into vivid visual and olfactory hallucinations, from their Vietnam experiences of twenty years earlier.

a) Psychedelic drugs: In 1938, Hoffman (8) synthesized a new compound he thought could have analeptic properties. Eventually, he carried out a self-experiment in which he ingested lysergic acid diethylamide (LSD) and reported: "[It] surged upon me an uninterrupted stream of fantastic [kaleidoscopic-like]images of extraordinary plasticity and vividness". He also noticed, the phenomena of synesthesias (receiving stimuli through a different sensory channel, such as seeing voices, or hearing colors), and trailing (moving objects are seen as a series of discrete and discontinuous images similar to stroboscopic photography or discotheque light effects).

Phencyclidine (PCP), as well as peyote, mescal, psilocybin, and, rarely, cannabis, tetrahydrocannabinol (THC), and the "phenylethylamine designer drugs", (3-4-methylene-dioxy- methamphetamine, (Ecstasy) 3-5 methylene-dioxy-etamphetamine (Eve), ("Ice"), methamphetamine consumed through smoking can generate bizarre, colorful visions with peculiar forms such as lattice, grating, or spirals. Artists and aesthetes of the “fin de siecle” such as Poe, Coleridge, de Quincey, Baudelaire and Gauthier, used hashish and opiates as means to increase their visual imagery and artistic creativity.

b) Prescriptions and Over the Counter Medications (OTC)

Some of the pharmacological agents that might generate hallucinations are the following: Alpha-adrenergic agonist anti- hypertensives like clonidine the anti-parkinsonian agents such as bromocriptine, selegiline, and carbidopa the anti-convulsant carbamazepine analgesics like pentazocine and fentanyl and anti-vertigo drugs like diphenidol. Also the psychotropic agents with robust anti-cholinergic effects, as well as the serotonin re-uptake blocker antidepressants (SSRI). The histamine-2 blocker used in the treatment of peptic ulcer disease are also capable of generating hallucinations. Antiarrhythmic agents, such as tonocaide, may be hallucinogenic in close to 12 % of patients.

Finally, dronabinol, an antiemetic cannabinoid used in the treatment of nausea associated with chemotherapy, can generate hallucinations in up to 5 % of cases (9).

a) Chromatopsias are illusions in which the environment is seen as uniformly tinted with a color. Xanthopsias (yellow vision) have been reported with Digitalis use (10), and purple vision may be seen with Santonin, an anti-helminthic (11).

b) Size hallucinations: Lilliputians are real hallucinations in which the patients see imaginary people of a small size, usually associated with pleasant feelings. Brodnignagian hallucinations, are just the opposite, people may be seen as giants.

c) Metamorphosias, are visual illusions (12). They may include the following: Dysmegalopsia, (alterations in the form of objects), micropsia and macropsia in which real visual perceptions are seen smaller or larger than they really are. Micropsia can be accompanied by teleopsia, in which the minified object is seen far away. In pelopsia objects are seen as getting closer. Allesthesia modifies the perception of the place where a true object really is. Palinopsia, is a persistent visual sensation after the object has been removed from the patient's visual field. These events have more an illusory than hallucinatory quality, and are frequently associated with either parietal lobe pathology or as a component of a migrainous aura.

2).- Tactile (haptic), proprioceptive, somatic, and visceral hallucinations.

Drug related: Formicative hallucinations are tactile phenomena found with the abuse of Alcohol, Methylphenidate, Amphetamines, and Steroids. The patients complain of "bugs" crawling in their skin, and may vigorously scratch themselves. Some of the most severe, chronic cases have been successfully treated with the neuroleptic pimozide (13). Use of Amyl nitrate (14) as an inhalant may arouse erotic sensations in the genital area. It has also been used to evoke a sense of prolonged orgasmic pleasure.

a) Epilepsy. Abnormal electric activity in diverse brain localizations may elicit hallucinatory phenomena of a peculiar nature. Alajouanine (15) quotes from Dostoyevsky's experience of an auditory aura and a sense of Epiphany: "The air was filled with a big noise and I thought it had engulfed me. I have really touched God. [No one] can imagine the happiness [epileptics] feel the second before our fit. Mahomet, in the Koran, said he has seen the Paradise. I don't know if this felicity lasts for seconds, hours or months, but, for all the joys life brings, I would not exchange this one".

Penrose and Wilder (16) reported many kinds of sensory seizures, such as feelings of numbness, tingling, heat, or water running in patients with centro-parietal foci. Abnormal electric hallucinations. Occipital cortical discharges can generate elementary visual hallucinations such as light spots, twirling objects, and geometrical figures. Etiology may include, traumatic cortical scars, post-concussion syndrome, neoplasms, infarctions, vascular malformations, lupus erythematous, degenerative, vasculitic lesions, or metabolic insult.

Olfactory, or uncinate seizures, are mostly reported as unpleasant odors, such as burning rubber, feces, rotting manure, sulfur, or indescribable. Frequently, the olfactory hallucinations are associated with aural gustatory hallucinations. The patient may describe elementary tastes like sweet, salty, bitter, or odd flavors.

Gustatory hallucinations are seldom found as an early sign of cognitive derrangement. One of our veterans, began to complain of having a bad taste in his mouth. Eventually, he believed that a pocket of poison has been implanted in his teeth by his dentist, and that he could bite himself and die. Further decline and clinical evolution pointed toward early manifestations of Alzheimer's Dementia. Patients suffering from psychotic depression may also, report the illusion of bad taste in their mouth (17).

Peduncular hallucinations: They originate from lesions of the mid-brain tegmentum. They may be elaborated and complex, rich in color, and depict landscapes, familiar faces, buildings, or lilliputian visions. Feeling tone may be absent, and the patient witnesses them with calm amusement.

Auditory and Vertiginous Hallucinations:
1.- Auditory: Stimuli of the transverse gyrus of Heschl of the temporal lobe, may elicit auditory events. Sacks (18) quotes on Dimitri Shostakovich, the Soviet composer, who reportedly had a metallic shell fragment in the temporal horn of his left ventricle. He said "since the fragment has been there, each time [I lean] my head to one side, I can hear music - different each time!" Apparently he would use this method while composing, producing melodic models for his symphonies.

2.- Vertiginous: Meniere's disease is the cause of severe kinesthetic hallucinations , accompanied by nausea, dizziness, and malaise. It may be also have tinnitus, often described as "chirping", or as the sound of crickets. This must be clinically differentiated from acoustic neuroma, vertebro-basilar artery syndromes, and other posterior fossa entities.

Autoscopic hallucinations: These are a blend of visual and proprioceptive hallucinations. Lhermitte has defined them as "the visual hallucination of the self" (19). In these cases, the vision is of one's double, like in a mirror, sometimes repeating one's gestures, and on occasions busy with other activities, a veritable doppelg„nger (6). They may be secondary to hypnopompic hallucinations, migraine, seizure disorders, delirium, encephalitis, post-concussion syndrome, or even non-neurological events such as: transcendental meditation, mystic events, use of hallucinogens, and near death experiences.

Sleep Disorders. Have shown a variety of perceptual disturbances.

1.-Narcolepsy-Cataplexy (Gelineau): Aldrich (20) has reviewed the syndrome and reports the symptomatology of hypnagogic hallucinations (before falling asleep), sleep paralysis, and cataplexy sometimes triggered by a strong emotion or during a laughing attack. He believes these phenomena are a dissociated manifestation of REM Sleep, with an increased excitability of the giant cells of the pontine-reticular formation that allow visions to intrude into wakefulness.

Mellman and co-authors (21) reported two PTSD patients who experienced sleep disturbances and recurrent daytime hallucinations. Further studies confirm these patients suffered from narcolepsy as well. They assert that the content of PTSD symptoms and narcolepsy tended to dissociate, and that the PTSD symptomatology remitted while narcolepsy persisted and progressed.

Hypnopompic hallucinations: Siegel (22) reports once being overwhelmed by a very vivid hypnopompic vision (when waking up). He had a "sense of pressure in his chest from a being, talking in reverse, rendering him unable to move". He compares the experience, to the ones reported in medieval religious literature as a succubus, (a she-devil), versus incubus (a he- devil).

Variant Angina. A 67 year old WWII veteran had a repeated hypnopompic vision of his platoon fighting toward a Japanese machine-gun nest. At the end of his dream, he had been shot in the chest and experienced a tearing, excruciating pain. He would wake up with tachycardia, cold sweats, and a sense of impending doom. After further cardiovascular evaluation, including challenge tests, he was diagnosed as having a Prinzmetal variant angina. This coincides with other clinical observations of ischemic episodes while awakening from nightmares (23).

Sleep Apnea: Another veteran, (24) seen by us had repeated complaints of mild memory impairment, restless sleep, loud snoring and sleep paralysis. He had a repetitive frightening hallucinations of a dead former girlfriend, "with a long gown, a dagger in her hand, and transparent like smoke". He experienced substantial improvement of his Sleep Apnea after being placed on protriptyline, losing 40 pounds, and having an uvulo-palato-pharyngoplasty and adeno-tonsillectomy.

Migraine attacks can be the cause of a variety of perceptual distortions. Most frequently though, the so called, "fortification spectra" hallucinations (teichopsia) are seen. They may show as irregular, colored, shimmering, edged, scintillating crescents, developing close to the center of the visual field. Sacks (18) believes that the visions of St. Hildegarde, a 12th century mystic, were typical migrainous hallucinations. Patients with classic migraine (25) suffer from perfusion changes either in the retina or in the visual pathway. Therefore, hallucinations of various geometric shapes, zigzag, or turrets can be seen. Rarely migraine can produce an upside-down vision of an observed object.

The Alice in Wonderland syndrome has been recently reported (26). It involves hallucinatory feelings of change in the body image. One migrainous patient reported " I get all tired out from pulling my head down. [It feels] like a balloon, my neck stretches and my head goes up to the ceiling". LSD users and children suffering from Epstein-Barr virus infection have reported similar symptoms.

Experimental stimulation of the cortex: Penfield (27), while operating on epileptic patients at the Montreal Neurological Institute (MNI), stimulated various areas of the cortex. These were cooperative, fully conscious patients during the neurosurgical procedure, and could give accurate descriptions. He was able to elicit vivid imagery of what appear to have been previous, trivial life events. In the operating room, patients reported voices of friends, songs heard long ago, or pleasant, nostalgic reveries of youthful gatherings. He postulated that "somewhere in the brain of each of us there is a continuous ongoing record of the stream of consciousness, from birth to death" (28).

Rarely, some medical entities such as diabetes mellitus, multiple sclerosis, serous otitis media and intra-otic foreign bodies can generate unusual sounds, clicks, murmurs, roars, humming, buzzing or whizzing as was reported by Coleman back in 1894 (29).

a) Entoptic hallucinations are related to lesions or abnormalities somewhere within the visuo-neural pathways. Roberts (11) has mentioned the post-cataract surgery delirium called "Black Patch disease". New surgical techniques have made its occurrence obsolete. Recently Holroyd et al (30) reported visual hallucinations in patients with macular degeneration with the associated risk factors of living alone, history of stroke and bilateral worsening of visual acuity. This points to a dual etiology of sensory deprivation, and decreased cortical inhibition.

b) Charles Bonnet's syndrome is a clinical entity of the elderly, first described by the Swiss naturalist, as an account of the visual hallucinations experienced by his grandfather. He described them as "amusing and magical visions, coexisting with reason" (31). It is now defined as a persistent recurrent visual hallucinatory phenomenon of a pleasant nature, with a clear state of consciousness, compelling, but seen by the patient as unreal. It is associated with ocular pathology, and tends to be "remarkably crisp and detailed, and at times lilliputian".

Some veterans who were under continuous enemy fire, or who served in heavy artillery units complain of permanent bilateral noises, and tinnitus. The frequent exposure to high decibel sounds as in heavy metal rock bands, percussion instruments, and jackhammers may produce persistent noises once the stimulus has ceased. The incessant rattle of a train's wheels may eventually sound like rhythmic, illusory, repetitive phrases.

Mirages are visual illusions such as those seen while driving and seeing wet pavement at a distance. They are due to a combination of individual factors and the reflection of light through different densities of heated air. Continuous work with computer and TV monitors may bring flickering in the visual fields.

They have been defined as hallucinations that the patient knows to be such (1). Although the perception is rather vivid and crisp, the patient has the insight that it has no external foundation. Therefore, its primary characteristic is the awareness of the unreality of the hallucinatory experience. The cases with obtunded sensorium portend a worse prognosis.

a) Radio-reception. A 35 year old Vietnam combat, veteran (32) started to complain of depression, headaches, and hearing blurred voices and music. Skull X-rays showed shrapnel metallic densities in the soft tissues and cranial bones of the left parieto-occipital region. His perception of voices and music were matched with stations in the AM broadcast band, and consistently identified the same station in the 560 Khz range. His radio- reception involved the metal implant diode rectification of the radio signal, and its bone transmission to the auditory apparatus. Other cases of broadcast reception due to dental work have been reported as well.

b) Virtual reality. A contemporary equivalent of the psychedelic culture has emerged with the use of "high-tech" interactive electronic gadgetry. These self-induced illusions of an alternate, parallel world may seem authentic and propel a compelling imagery. There is a potential for dependency in these pseudo-hallucinatory experiences of cyberspace.

Hallucinations and illusions, are part of a continuum of perceptual disturbances with manifold variations. They may entail idiosyncratic forms of bodily communication, or transfer of information from within or without. In the context of mental illness they are supported by thought disorder and crystallized delusional system. In states of delirium, drug intoxications, or neurological dysfunction, they may be perceived as transient, bewildering, unreal phenomena.

For the proper clinical management of a hallucinating patient, it is of the utmost importance to rule out a medical or neurological entity, perhaps an adverse drug reaction or use of hallucinogens within the context of a culturally validated phenomena. A psychiatric diagnosis should only be arrived at after a judicious evaluation of the phenomenology of the hallucinatory phenomena, circumstances in which they appear, and concomitant symptoms. In some instances, a psychiatric consultation may be in order.

1.- Hinsie L and Campbell R. Psychiatric Dictionary. Fourth Edition, Oxford University Press. New York, 1970.

2.- American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised, American Psychiatric Association Press. page 113, Washington DC, 1987.

3 .-Roberts, D. Geronimo. National Geographic. 182: 46-71, October 1992.

4.- Solomon PH, Leiderman HE, Mendelson JA et al. Sensory Deprivation: A Review. Am. J. Psychiatry. 114: 357-363, 1957.

5.- Sacks OL. Seeing Voices: A Journey intro the world of the deaf, page 7, Univ. of California Press. Los Angeles, 1989.

6.- Boza RA, Milanes FE, Hanna GS and Trujillo MO. Psychiatric symptoms associated to Parietal Lobe Dysfunctions. Resident & Staff Physician. 39 (1):59-68, January 1993.

7.- Cohen, SI. Flashbacks. Drug Abuse & Alcoholism Newsletter. 6: No. 9, November 1977.

8.- Hoffman AL. The Discovery of LSD and subsequent investigations on naturally occurring hallucinogens. - Discovery in Biological Psychiatry -. page 91, Ayd FR & Blackwell BA, Eds. J.B. Lippincott Co. Philadelphia, 1970.

9.- Sifton DA and Mehta MU. PDR's Drugs Interactions and Side Effects System. Computer Database. Medical Economics Data. Release 3.1. Update September 1992.

10.-Lessell SI. Visual hallucinations and related phenomena. Weekly Update: Neurology and Neurosurgery. 2 (6): 48-54. Biomedia. Princeton, New Jersey, February 1980.

11.-Roberts JE. Differential Diagnosis in Neuropsychiatry. Chapter 16, Disorders of Perception, pages 258-271, J. Wiley & Sons. New York, 1986.

12- MacDonald, Critchley: "The Parietal Lobes." London. Hafner Press, 1953.

13.-Johnson GE and Anton RA. Delusions of parasitosis: differential diagnosis and treatment. Southern Medical Journal. 78 (8): 914-918, August 1985.

14.-Sigell LE, Kappa FR, Fusaro GR, et al. Popping and snorting volatile nitrites: A current fad for getting high. Am. J. Psychiatry. 135 (1): 1216-1218, Oct 1978.

15.-Alajouanine, T. Dostoiewsky's Epilepsy. Brain 86: 209-218 June 1963.

16.-Penrose RI and Wilder JO. Epilepsy: The Seizure - Variations on a Theme. pages 30-32. Neurology Series. F.A. Davis Co. Philadelphia, 1968.

17.-Carter JE. Visual, Somatosensory, Olfactory and Gustatory Hallucinations. The Interface of Psychiatry and Neurology. Psychiatric Clin. of N. America. 15 (2): 347-358, June 1992.

18.-Sacks, OL. The Man who mistook his Wife for a Hat: Chapter 15. Reminiscence, page 134, Chapter 20. The visions of Hildegard, page 160. Summit Books, New York, 1985.

19.-Lhermitte, JE. Visual hallucinations of the self. British Medical Journal. 1:431-434, March 3, 1951.

20.-Aldrich MI. Review Article: Narcolepsy. NEJM. 323 (6): 389-394. August 9, 1990.

21.-Mellman TO, Ramsay EU, and Fitzgerald ST. Divergence of PTSD and Narcolepsy associated with military trauma. Journal of Anxiety Disorders. 5:267-272, 1991.

22.-Siegel RO. Fire in the Brain: Clinical Tales of Hallucinations. Penguin Books. New York, 1992.

23.-Otsuka KO, Yanaga TA and Watanabe HA. Variant Angina and REM Sleep. American Heart Journal. 115: 1343-1345. June 1988.

24.-Boza RA, Trujillo MO, Millares SY, et al. Sleep Apnea and associated neuropsychiatric symptoms: A case report. VA Practitioner 1 (8):43-45, August 1984.

25.-Selby, GE. Migraine and its Variants. In Current Diagnoses - 5 Ed., page 961. Conn HO and Conn RE. W.B. Saunders & Co. Philadelphia, 1977.

26.-Rolak LO. Literary neurologic symptoms: Alice in Wonderland. Arch. Neurology. 48 (6): 649-651, June 1991.

27.-Penfield WI and Jasper HE. Epilepsy and the functional anatomy of the human brain, pages 453-461. Little Brown Co. Boston, 1954.

28.-Milner BR. In Memory Mechanisms. From Wilder Penfield: His Legacy to Neurology. Canadian Med. Journal. 116: 1365-1377, 1977.

29.-Colman WS. Hallucinations in the sane associated with local organic disease of the sensory organs. British Med. Journal 1 (1894): 1015-1017. May 12, 1894.

30.-Holroyd S, Rabins P, Finkelstein D, et al. Visual hallucinations in patients with macular degeneration. Am. J. Psychiatry. 149 (12): 1701-1706, December, 1992.

31.-Gold KE and Rabinds PE. Isolated Visual Hallucinations and the Charles Bonnet Syndrome: A Review of the Literature and Presentation of Six Cases. Comp. Psychiatry 30 (1): 90-98, January/February 1989.

32.-Boza RA and Liggett ST. Pseudohallucinations: Radio-reception through shrapnel fragments. Am. J Psychiatry. 138 (9): 1263-1264, September 1981.


Vivid dreams or bizarre dreams that stay with you

Vivid dreams may arise for a variety of reasons. They may indicate you are suffering from certain medical conditions, which might include neurodegenerative disorders like Parkinson's disease. There are other, less frightening reasons for your weird dreams as well, so don't jump to conclusions too quickly.

This may come as a surprise to you, but particularly bizarre or memorable dreams might also indicate a possible infection. "Any infection increases the amount of slow-wave sleep we have, however, this delays the starting point of when we enter dreaming sleep, so dreaming sleep starts late, and can erupt into consciousness. This leads to vivid dreams and strange hallucinations," Dr. Patrick McNamara, a neurologist from Boston University Medical School, told the International Business Times.

Alcohol can also prompt vivid and memorable dreams. This is because the effects of alcohol wear off toward morning, affecting your brain chemicals and triggering bizarre and sometimes scary dreams.

Like alcohol, medications like antidepressants can also trigger vivid dreams, said Dr Patrick McNamara of the Boston University Medical School. "They've been shown to make REM bursts more intense in the people who take them," says Deirdre Barrett, Ph.D., assistant clinical professor of psychiatry at Harvard Medical School in Boston and author of The Committee of Sleep. "And most of those people seem to have more nightmares as a side effect." If your medications are interfering with your sleep and your dreams, discuss them with your doctor. It might be time to switch medications.


The Ancient, Peaceful Art of Self-Generated Hallucination

Cornelia Kopp via Flickr

A fter five years of practicing meditation, subject number 99003 began to see the lights. “My eyes were closed,” he reported, “[and] there would be what appeared to be a moon-shaped object in my consciousness directly above me, about the same size as the moon if you lay down on the ground and look into the night sky. It was white. When I let go I was totally enveloped inside this light… I was seeing colors and lights and all kinds of things going on… Blue, purple, red. They were globes they were kind of like Christmas-tree lights hanging out in space, except they were round.”

Subject 99003 described these experiences to Jared Lindahl, a researcher from Warren Wilson College in Asheville, North Carolina, who has spent years scientifically studying meditation. He and his team are the midst of a large study on meditators and their experiences, and in a recent paper they homed in on a peculiar experience many of them share: mysterious lights that appear in their mind’s eyes as they practice.

To figure out just where these lights might be coming from, Lindahl and his team talked to 28 meditators for an average of 77 minutes each. Nine of them reported “light experiences,” with descriptions much like subject 99003’s. “Sometimes there were, oftentimes, just a white spot, sometimes multiple white spots,” one said. “Sometimes the spots, or ‘little stars’ as I called them, would float together in a wave, like a group of birds migrating, but I would just let those things come and go.”

Another said: “In concentration I’ve had rays of white light that go through everything. They’re either coming from behind me somewhere or coming out of the object that I was concentrating on… I saw it with my eyes open and it wasn’t really seeing it was something else, even though I still was perceiving that I was there.”

Buddhist literature refers to lights and visions in myriad ways. The Theravada tradition refers to nimitta, an vision of a series of lights seen during meditation that can be taken to represent everything from the meditator’s pure mind to a visual symbol of a real object. In one Buddhist text, called The Path of Purification, the nimitta is described this way:

It appears to some as a star or cluster of gems or a cluster of pearls, […] to others like a long braid string or a wreath of flowers or a puff of smoke, to others like a stretched-out cobweb or a film of cloud or a lotus flower or a chariot wheel or the moon’s disk or the sun’s disk.

Other Buddhist traditions also refer to lights during meditation, but Lindahl points out in the paper that “there is no single, consistent interpretation of meditation-induced light experiences in Buddhist traditions.” And yet the appearance of lights isn’t a fluke occurrence—it’s something that many meditators experience, and that many traditions have tried to incorporate and explain.

“Sometimes the spots, or ‘little stars’ as I called them, would float together in a wave, like a group of birds migrating, but I would just let those things come and go.”

So where are these lights coming from? They’re clearly not real, physical lights dancing in front of the meditator’s face, but rather a construction of the idle, meditating brain. What is it about meditation that opens the brain up to these kinds of hallucinations?

To answer that question, Lindahl and his team looked for occasions where the descriptions he gathered from meditators intersected with descriptions of neurophysiological disorders. They found that both the first-person accounts and the Buddhist literary descriptions of these lights intersected pretty well with the experiences of people undergoing the intentional practice of sensory deprivation.

Hallucinations are relatively well-documented in the world of sensory deprivation, and they dovetail with the lights seen by meditators. Where meditators describe jewel lights, white spots and little stars, those under sensory deprivation sometimes describe dots and points of light. Where meditators see shimmering ropes, electrical sparks, and rays of light that go through everything, the sensory deprived might see visual snow, bright sunsets, and shimmering, luminous fog. Neuroscientists think that when the eyes and ears are deprived of input, the brain becomes hypersensitive and neurons may fire with little provocation, creating these kinds of light shows. Lindahl suspects that the lights that meditators see are the result of the same phenomenon—that meditating is itself a mild form of sensory deprivation.

In some ways, this is not surprising. Meditation often involves being alone, in a quiet, dimly lit room. Some Tibetan Buddhists practice what’s called “mun mtshams,” or “dark retreat,” in which they close themselves off in the dark. And it’s not just about the physical spaces where meditation happens—many forms of meditation are focused on isolating a single stimulus and shutting out everything else, a kind of mental sensory deprivation. By focusing on breath, a specific vision, a single object, or something else as they get into the zone, meditators are “guarding the sense doors” from the rest of the world. This may be an ancient trick for creating a space of intentional sensory deprivation and opening oneself up to the dazzling light show that often follows.


Hallucinations Seen as Another Troubling COVID-19 Symptom

by Stacey Colino, AARP, October 6, 2020 | Comments: 0

En español | Jamie Colvin-Choate thought she was tied to a bed while bugs crawled over her, that she heard her friends plotting against her, and that, at 65, she'd just had a baby — all while hospitalized for a severe COVID-19 infection last summer.

Colvin-Choate nearly died twice, had a tracheotomy and a feeding tube inserted, and was put into a medically induced coma. But she counts the hallucinations she suffered, and “having to decipher what was real and what wasn't after I came through,” as the hardest part of her ordeal.

For the latest coronavirus news and advice go to AARP.org/coronavirus.

When Drew Murrie, hospitalized for COVID-19, woke up in the ICU last spring, he remembered vivid images of being stuck in a cave stacked with skeletons, of electric butterflies flying around the room and, at one terrifying moment, of a human hand covering his face while he was in bed. “I had never had visions like this before,” says Murrie, 59, who lives with his family in the Chicago suburbs. “I had no idea what was going on.”

According to a recent review of studies in Psychology Research and Behavior Management, COVID-19 infections have been triggering such hallucinations, as well as things like delusions and paranoia in patients with no history of mental health issues. Such temporary symptoms of psychosis have become yet another surprising effect the virus has on the brain. In some patients, hallucinations may be part of the delirium that accompanies a long COVID-19 illness or hospital stay in others, these visions can occur on their own. A study released this week and conducted at the Northwestern Medicine health system showed that up to one-third of hospitalized patients showed “altered mental function,” a term that includes things like delusions, as well as confusion and unresponsiveness. (Unlike hallucinations, however, these neurological symptoms can have a long-term impact.)

It's not fully understood why this happens, but one idea is that patients with severe COVID-19 infection “may have a little brain damage from chronically low levels of oxygen going to the brain, due to COVID causing the lungs not to oxygenate the blood as well,” explains Pravin George, a staff neurointensivist at Cleveland Clinic. “It could also be that COVID itself is attacking the brain directly in certain patients.”

The disease caused by the virus may also trigger inflammation in areas of the brain that could cause symptoms like hallucinations. And powerful medications, such as steroids, which are used to reduce inflammation could also be a cause in some, notes psychiatrist Stephen Ferrando, M.D., director and chair of the Department of Psychiatry at Westchester Medical Center in Valhalla, New York. The body's response to inflammation could also contribute, he adds, since “the immune cascade or cytokine storm behind COVID may play a role in triggering a variety of mental health problems.”

In some patients, hallucinations — which can be as subtle as detecting a burnt-rubber smell when none exists — precede hospitalization and can be a red flag for doctors. “When people present with hallucinations or delusions in the ER, we now test for COVID,” Fernando says.

Such was the case with Marilyn Schneider, 57, who spiked a 104.5 fever in late March. To stay on top of what she needed to do while feeling ill, she posted notes around her home, reminding her to wake up her son at a certain hour for school and to feed the dog and let him out. (Her dog had died six years earlier and her 24-year-old son is in graduate school.)

"I was in a twilight zone while my fever was high,” recalls Schneider, an executive secretary at the Cleveland Clinic Fairview Hospital. “I never had hallucinations before — I don't even dream — so this was very odd for me.” When she rolled over in bed and saw an image of herself pleading for help, she called 911 and ended up in the hospital ICU. That vision may have saved her life.


Examples of Delusions

Any persistent and false belief may be a delusion, but as with hallucinations there are some common types and categories of delusions, most often triggered by a mental illness or psychotic episode:

  • Persecutory. These are delusions in which a person believes someone is out to get them or is mistreating them.
  • Grandiose. A grandiose delusion is any belief relating to having special powers, relationships with someone important or famous, or having exceptional talents or abilities.
  • Jealous. Delusions of jealousy involve believing a partner is being unfaithful.
  • Somatic. A false belief that one is sick or physically disabled is somatic.
  • Bizarre. Delusions are often non-bizarre, meaning they could be true but aren’t. Bizarre delusions are those that could not be true, such as believing someone is controlling one’s mind.


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