What are hallucinations?
People having hallucinations sense things that are not
real, even though they seem very real to the person having
them. Hallucinations may involve any of the senses, such
as:
- hearing voices when no one is speaking
- seeing things that are not there
- feeling things crawling on you that are not there
- smelling scents that are not there
- tasting flavors that are not there.
Smell and taste hallucinations are rare.
Hallucinations are not the same as illusions. Illusions are
when you see or hear something and think it is something
else. An example is a person who sees a lamp out of the
corner of their eye and thinks it is a person. A person
having hallucinations may be completely out of touch with
reality.
How do they occur?
Some causes of hallucinations include:
- fever, especially in children and older adults
- serious illness such as liver failure, kidney failure, or brain cancer
- mental disorders such as schizophrenia or bipolar
disorder
- brain damage
- dehydration
- side effects of medicine
- severe lack of sleep
- stress
- drugs such as LSD, poisonous mushrooms, or PCP
- heavy alcohol use or withdrawal.
Some people have hallucinations right before they get a
migraine or have a seizure.
What are the symptoms?
There are different kinds of hallucinations:
- Visual hallucinations may be unformed shapes or colors,
or things such as animals or people. The person sees
things that no one else can see. Drugs like LSD may cause
visual hallucinations. Blind people sometimes have
hallucinations of seeing things. People with dementia
also may have this kind of hallucination.
- Auditory hallucinations occur when a person hears voices or sounds that no one else hears. People with
schizophrenia often have this type of hallucination.
Deaf people may have hearing hallucinations. This type
also occurs from using cocaine, amphetamine or other
similar drugs.
- A tactile hallucination is the feeling of something
crawling on the skin. These kind of hallucinations most
often occur when drugs or alcohol are used.
How are they diagnosed?
Your health care provider will ask about symptoms and
examine you. He or she will make sure that a medical
problem or mind-altering drugs, such as LSD or cocaine, are
not causing the symptoms.
If no medical cause can be found, you may be referred to a
mental health professional for further testing.
How are they treated?
Treatment for hallucinations depends on the cause. If
hallucinations are rare, or if they do not trouble the
person, no treatment may be needed.
Hallucinations caused by mental health disorders, such as
schizophrenia can generally be controlled with medicine. If
hallucinations are caused by medicine, changing the dose of
medicines may correct the problem.
Hallucinations can be scary for the person having them and
for anyone around them. When someone is having
hallucinations, it is important to keep calm. If someone is
having constant or severe hallucinations, call for emergency
help.


Disclaimer: This content is reviewed periodically and is subject to
change as new health information becomes available. The
information provided is intended to be informative and educational and is not a
replacement for professional medical evaluation, advice, diagnosis or
treatment by a healthcare professional.
HIA File BHV3331F.HTM Release 9.0/2006. Copyright © 2006 McKesson Corporation and/or one of its subdiaries. All Rights Reserved.
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