Hallucinations involve sensing things while awake that appear to be real, but instead have been created by the mind.
Common hallucinations include any of the following:
In some cases, hallucinations are normal. For example, hearing the voice of, or briefly seeing, a loved one who recently died can be a part of the grieving process.
There are many causes of hallucinations, including:
A person who begins to hallucinate and is detached from reality should get checked by a health care professional right away. Many medical and mental conditions that can cause hallucinations may quickly become emergencies. The person should not be left alone.
Call the health care provider, go to the emergency room, or call the local emergency number (such as 911).
A person who smells odors not present in his surroundings should also be evaluated by a health care professional. These hallucinations may be caused by a serious underlying medical condition.
The health care provider will do a physical examination and take a medical history. The person will be asked about the hallucinations. For example, how long the hallucinations have been happening, when they occur, or whether the person has been taking medications or using alcohol or illegal drugs.
Blood may be drawn for testing.
American Psychiatric Association. Diagnostic and statistical manual of mental disorders. 5th ed. Arlington, Va: American Psychiatric Publishing. 2013.
Freudenriech O, Weiss AP, Goff DC. Psychosis and schizophrenia. In: Stern TA, Rosenbaum JF, Fava M, Biederman J, Rauch SL, eds. Massachusetts General Hospital Comprehensive Clinical Psychiatry. 1st ed. Philadelphia, Pa: Elsevier Mosby; 2008:chap 28.
Hockberger RS, Richards JR. Thought disorders. In: Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. 8th ed. Philadelphia, Pa: Elsevier Mosby; 2013:chap 110.
Updated by: Fred K. Berger, MD, Addiction and Forensic Psychiatrist, Scripps Memorial Hospital, La Jolla, California. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.
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