Halcion see Triazolam

Haldol see Haloperidol

Hallucinations

Description

A hallucination is a false perception occurring without any identifiable external stimulus and indicates an abnormality in perception. The false perceptions can occur in any of the five sensory modalities. Therefore, a hallucination essentially is seeing, hearing, tasting, feeling, or smelling something that is not there. The false perceptions are not accounted for by the person's religious or cultural background, and the person experiencing hallucinations may or may not have insight into them. Therefore, some people experiencing hallucinations may be aware that the perceptions are false, whereas others may truly believe that what they are seeing, hearing, tasting, feeling, or smelling is real. In cases when the person truly believes the hallucination is real, the individual may also have a delusional interpretation of the hallucination.

Hallucinations must be distinguished from illusions, which are misperceptions of actual external stimuli. In other words, an illusion is essentially seeing, hearing, tasting, feeling, or smelling something that is there, but perceiving it or interpreting it incorrectly. An example of an illusion might be hearing one's name called when the radio is playing. There is an external auditory stimulus, but it is misperceived. True hallucinations do not include false perceptions that occur while dreaming, while falling asleep, or while waking up. Unusual perceptual experiences one may have while falling asleep are referred to as hypnagogic experiences. Unusual perceptual experiences one may have while waking up are referred to as hypnopompic experiences. Hallucinations also do not include very vivid experiences one may have while fully awake (such as especially vivid daydreaming or imaginative play).

Hallucinations are a symptom of either a medical (e.g., epilepsy), neurological, or mental disorder. Hallucinations may be present in any of the following mental disorders: psychotic disorders (including schizophrenia , schizoaffective disorder , schizophreniform disorder , shared psychotic disorder , brief psychotic disorder , substance-induced psychotic disorder ), bipolar disorder , major depression with psychotic features, delirium , or dementia . Auditory hallucinations, in particular, are common in psychotic disorders such as schizophrenia.

Use of certain recreational drugs may induce hallucinations, including amphetamines and cocaine, hallucinogens (such as lysergic acid diethylamide or LSD), phencyclidine (PCP), and cannabis or marijuana. For example, visual hallucinations are commonly associated with substance use. Individuals may report false perceptions of little people or animals (sometimes referred to as Lilliputian hallucinations). In addition, withdrawal from some recreational drugs can produce hallucinations, including withdrawal from alcohol, sedatives, hypnotics, or anxiolytics. Withdrawal from alcohol, for instance, commonly causes visual hallucinations, especially at nighttime.

Types

Hallucinations are categorized according to which sensory modality is involved and, in addition, are categorized as either mood-congruent or mood-incongruent. The types of hallucinations are:

  • Auditory: The false perception of sound, music, noises, or voices. Hearing voices when there is no auditory stimulus is the most common type of auditory hallucination in mental disorders. The voice may be heard either inside or outside one's head and is generally considered more severe when coming from outside one's head. The voices may be male or female, recognized as the voice of someone familiar or not recognized as familiar, and may be critical or positive. In mental disorders such as schizophrenia, however, the content of what the voices say is usually unpleasant and negative. In schizophrenia, a common symptom is to hear voices conversing and/or commenting. When someone hears voices conversing, they hear two or more voices speaking to each other (usually about the person who is hallucinating). In voices commenting, the person hears a voice making comments about his or her behavior or thoughts, typically in the third person (such as, "isn't he silly"). Sometimes the voices consist of hearing a "running commentary" on the person's behavior as it occurs ("she is showering"). Other times, the voices may tell the person to do something (commonly referred to as "command hallucinations").
  • Gustatory: A false perception of taste. Usually, the experience is unpleasant. For instance, an individual may complain of a persistent taste of metal. This type of hallucination is more commonly seen in some medical disorders (such as epilepsy) than in mental disorders.
  • Olfactory hallucination: A false perception of odor or smell. Typically, the experience is very unpleasant. For example, the person may smell decaying fish, dead bodies, or burning rubber. Sometimes, those experiencing olfactory hallucinations believe the odor emanates from them. Olfactory hallucinations are more typical of medical disorders than mental disorders.
  • Somatic/tactile hallucination: A false perception or sensation of touch or something happening in or on the body. A common tactile hallucination is feeling like something is crawling under or on the skin (also known as formication). Other examples include feeling electricity through one's body and feeling like someone is touching one's body but no one is there. Actual physical sensations stemming from medical disorders (perhaps not yet diagnosed) and hypochondriacal preoccupations with normal physical sensations, are not thought of as somatic hallucinations.
  • Visual hallucination: A false perception of sight. The content of the hallucination may be anything (such as shapes, colors, and flashes of light) but are typically people or human-like figures. For example, one may perceive a person standing before them when no one is
    Colored positron emission tomography scan (PET scan) of the brain of a patient with schizophrenia who is experiencing a hallucination. Highlighted areas show brain activity. The patient's hallucination consisted of heads that spoke to him. The active areas of the brain seen here (the auditory and visual areas) confirm that the patient "saw" and "heard" the heads in the hallucination. (Wellcome Dept of Cognitive Neurology. Photo Researchers, Inc./Science Source. Reproduced by permission.) See color insert for color version of photo.
    Colored positron emission tomography scan (PET scan) of the brain of a patient with schizophrenia who is experiencing a hallucination. Highlighted areas show brain activity. The patient's hallucination consisted of heads that spoke to him. The active areas of the brain seen here (the auditory and visual areas) confirm that the patient "saw" and "heard" the heads in the hallucination.
    (Wellcome Dept of Cognitive Neurology. Photo Researchers, Inc./Science Source. Reproduced by permission.)
    See color insert for color version of photo.
    there. Sometimes an individual may experience the false perception of religious figure (such as the devil, or Christ). Perceptions that would be considered normal for an individual's religion or culture are not considered hallucinations.
  • Mood-congruent hallucination: Any hallucination whose content is consistent with either the depressive or manic state the person may be in at the time. Depressive themes include guilt, death, disease, personal inadequacy, and deserved punishment. Manic themes include inflated self-worth, power, knowledge, skills, and identity and a special relationship with a famous person or deity. For example, a depressed person may hear voices saying that he or she is a horrible person, whereas a manic person may hear voices saying that he or she is an incredibly important person.
  • Mood-incongruent hallucination: Any hallucination whose content is not consistent with either the depressed or manic state the person is in at the time, or is mood-neutral. For example, a depressed person may experience hallucinations without any themes of guilt, death, disease, personal inadequacy, or deserved punishment. Similarly, a manic person may experience hallucinations without any themes of inflated self-worth, power, knowledge, skills, or identity or a special relationship to a famous person or deity.

See also Alcohol and related disorders ; Major depressive disorder ; Substance abuse and related disorders ;

Resources

BOOKS

American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 4th edition, text revised. Washington, DC: American Psychiatric Association, 2000.

Kaplan, Harold I., M.D., and Benjamin J. Sadock, M.D. Kaplan and Sadock's Synopsis of Psychiatry: Behavioral Sciences, Clinical Psychiatry. 8th edition. Baltimore: Williams and Wilkins.

Jennifer Hahn, Ph.D.



User Contributions:

r
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Oct 14, 2007 @ 8:20 pm
I have been looking through the internet at sites like this because i was in hospital from sunday to tuesday there because i went into a drug induced psychosis, i believed that my friends were in my ward yet i couldnt see them and they were saying the worst things immaginable about me about the most personal things you can imagine, i also believed that all the nurses and doctors were talking about me, slagging me off, and could hear everything being said as clear as anything!! the voices stopped on tuesday after i was given tablets to make me sleep on monday. im still having real difficulties coming to terms with the fact it was not real voices i was hearing and have every day since then, relapsed for a few hours each day and started believing again that the voices were real. i've read so much about auditory hallucinations now but i havent really heard any stories were the voices are the voices of the persons friends and they are all in discussion about the person, they also commented on things i said to my mum or the psychiatrist.
K
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Dec 4, 2008 @ 6:18 pm
I started having olfactory hallucinations a few months ago (mainly a smoke smell.) The doctors ruled out seizure and tumor and are chalking it up to mental illness since I also have bipolar disorder. It is very annoying even when I figured out it wasn't something in the environment--or at least I don't think it is. I have a theory that it could be some kind of smell sensitivity, but it's not a very strong theory.

I'm also having a lot more migraines lately. I wonder if it could have a hormonal link?
Jordan
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Jan 30, 2010 @ 3:03 am
Since I was little, I have always seen, heard, and felt things that weren't there. I never told anyone (I'm only 14), but now I'm seriously thinking about it. One of the worst times was when I was 12. I had just woken up, and i saw a lion. At first it was cute, and i could touch it. It felt soft, and solid just like petting a real lion. Out of nowhere, though, it attacked me and bit my chest. I could feel every bit of it like it was normal! It turns out that the lion was my dad coming in to say good morning, and i was fighting against him. He thought I was crazy or something. I don't know where i got the biting feeling though. He didn't touch me, until he figured out what was going on. He eventually brought me back to reality, but neither of us are going to forget it soon...It was VERY scary.
Mherring
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Jul 1, 2010 @ 2:14 pm
I smell a chemical smell every now and then and it lasts from 1 day to weeks at a time. I can smell it with Every breath. I also have migraines but the two happen no where near eachother.
JoeSmith
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Nov 14, 2011 @ 1:13 pm
I've been recently experiencing some hallucinations. I'm 22 years old, was diagnosed ADHD quite a few months back, lets say 8 as I don't know for certain lol. Anyways, it started after I stayed up all night at a friends place, I'd taken some of my medication as it's helped me in so many different ways, however after returning home I'd started experiencing hallucinations. Keep in mind that I'd consumed no where near a dosage level of aformentioned medication in order for these hallucinations to begin from, so I figured it must have been sleep deprivation(not certain still). I'm prescribed 10mg extended release pills, which is the equivelent of 5mg being released instantly, and the other 5mg released 4 hours later, so the lowest dosage one could possibly get (it doesn't work that well actually, I don't take it on a regular bases, only when needed).

Visual hallucinations consisted of bending light, moving shadows( my bathroom door looked like it was closing just by how the shadow was moving, but the door remained still. Structure within the walls and doors of my house, warped in what I could only describe and compare as to the motion of a persons esophagus as food is forced down (weird, but interesting). Now here comes the really amusing/interesting parts, Auditory Hallucinations (Oh shit, that's bad I thought to myself). Disembodied breathing, and Music from no where, not just music, but very detailed music with regards to it's sound(like listening to the radio, except you can't turn it off): However, the lyrics where limited to a couple words at best and would often repeat themselves(at times I felt as if by saying(thinking) the words in my head I could increase the rate in which the song played them). Amusing, I thought to myself as I took note of every detail taking place around me. I wasn't scared, or shocked...if i'd felt any negative reaction towards the occurance it might have been one of annoyance as I've been busy writing about a particularly fascinating subject for school (University).

I also noted that the auditory hallucinations occured only when there was an initial source of sound, in this case it happened to be the furnace.
The Visual hallucinations where most notable when looking away from my computer monitor as my eyes had to adjust, for some reason this greatly enhanced the subsequent change in visuals.

Now this might have had something to do with the medication, I hope not because this is the first time i've hallucinated ever, even after months of taking the same medication at the same dosage. Conversely it may have been from lack of eating and poor nutrition as I regularly find myself no hungry when I know I should be(steals the appetite away it does), and because my circadian rythm is off.
Carol
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May 12, 2012 @ 7:19 pm
Just wondering if anyone has tried high doses of niacin (vitamin b) to stop this problem. I read about it while browsing the web. I am not very impressed by how some doctors are treating this illness here in the U.K and sometimes think that the U.S.A has more experience. I have read that you have to start with 25mg three times a day and work up to a higher dose. I think it has to be taken with vitamin c also so that it is properly absorbed.
doctoryourself.com
Hhhhh
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Sep 3, 2014 @ 5:17 pm
I've been hallucinating since I can remember, all five senses. I have a hard time determining wether they are real or not, and sometimes when things are real I'll ignore them because I think they're not. I am depressed (I've been suicidal on and off, but I'm okay right now). I've gone to doctors that think they are connected to my moods, but that doesn't make sense because I had them before I was depressed. Also I've been keeping track of them and they have made no connections to my moods. Some times they're in me sometimes they're outside. They'll talk to each other (sometimes about me) and directly to me. They scream and whisper things I can't make out. I see them, hear them, smell them, sometimes taste things like blood and feel them. Mostly it's the same ones that come back, but there are ones I've only seen once before. They are usually people, but not always. There are lots of animals and strange creatures. Sometimes just heads or distorted arms reaching through my bedroom walls.
I also have a ton of anxiety, I always have. Like doctors are amazed and if I took 25 Prozac a day it wouldn't even calm it down anxiety.
I need help.

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