Hallucination is a sensation or sensory perception that a person experiences in the absence of a relevant external stimulus. That is, a person experiences something that doesn’t really exist (except in their mind). They are distinguishable from several related phenomena, such as dreaming, which does not involve wakefulness; pseudohallucination, which does not mimic real perception, and is accurately perceived as unreal; illusion, which involves distorted or misinterpreted real perception; and imagery, which does not mimic real perception and is under voluntary control.Hallucinations also differ from “delusional perceptions”, in which a correctly sensed and interpreted stimulus (i.e., a real perception) is given some additional (and typically absurd) significance.
Hallucinations can occur in any sensory modality visual, auditory, olfactory, gustatory, tactile, proprioceptive, equilibrioceptive, nociceptive, thermoceptive and chronoceptive.A hallucination can occur in any sensory modality — visual, auditory, olfactory, gustatory, tactile, etc.
Types
The types of hallucinations include:
- An auditory hallucination – is an hallucination involving the sense of hearing. Called also paracusia and paracusis.
- A gustatory hallucination – is an hallucination involving the sense of taste.
- A hypnagogic hallucination – is a vivid dreamlike hallucination at the onset of sleep.
- Hypnopompic hallucination – is a vivid dreamlike hallucination on awakening.
- Kinesthetic hallucination – is an hallucination involving the sense of bodily movement.
- Lilliputian hallucination – is an hallucination in which things, people, or animals seem smaller than they would be in reality.
- Olfactory hallucination – is an hallucination involving the sense of smell.
- Somatic hallucination – is an hallucination involving the perception of a physical experience occurring with the body.
- Tactile hallucination – is an hallucination involving the sense of touch.
- Visual hallucination – is an hallucination involving the sense of sight.
Causes
Schizophrenia – More than 70% of people with this illness get visual hallucinations, and 60%-90% hear voices. But some may also smell and taste things that aren’t there.
Parkinson’s disease – Up to half of people who have this condition sometimes see things that aren’t there.
Alzheimer’s disease and other forms of dementia – They cause changes in the brain that can bring on hallucinations. It may be more likely to happen when your disease is more advanced.
Epilepsy – The seizures that go along with this disorder can make you more likely to have hallucinations. The type you get depends on which part of your brain the seizure affects.
Treatment
First, your doctor needs to find out what’s causing your hallucinations. He’ll take your medical history and do a physical exam. He’ll ask about your symptoms.
You may need tests to help identify the problem. For instance, an EEG, or electroencephalogram, checks for unusual patterns of electrical activity in your brain. It could show if your hallucinations are due to seizures.
You might get an MRI, or magnetic resonance imaging, which uses powerful magnets and radio waves to make pictures of structures inside your body. It can find out if a brain tumor or something else, like an area that’s had a small stroke, could be causing your hallucinations.
Your doctor will treat the condition that’s causing the hallucinations. The treatment can include things like:
- Medication for schizophrenia or dementias such as Alzheimer’s disease
- Antiseizure drugs to treat epilepsy
- Treatment for macular degeneration, glaucoma, and cataracts
- Surgery or radiation to treat tumors
- Drugs called triptans, beta-blockers, or anticonvulsants for people with migraines
Your doctor may prescribe pimavanserin (Nuplazid). This medicine has been effective in treating hallucinations and delusions linked to psychosis that affects some people with Parkinson’s disease.
Sessions with a therapist can also help. For example, cognitive behavioral therapy, which focuses on changes in thinking and behavior, helps some people manage their symptoms better.
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