Hallucination Health Article

Schizophrenia

The auditory hallucinations associated with schizophrenia may be the end result of a combination of factors. These hallucinations have sometimes been attributed to unusually high levels of the neurotransmitter dopamine in the patient's brain. Other researchers have noted abnormal patterns of brain activity in patients with schizophrenia. In particular, these patients suffer from dysfunction of a mechanism known as corollary discharge, which allows people to distinguish between stimuli outside the self and internal intentions and thoughts. Electroencephalograms (EEGs) of patients with schizophrenia that were taken while the patients were talking showed that corollary discharges from the frontal cortex of the brain (where thoughts are produced) failed to inform the auditory cortex (where sounds are interpreted) that the talking was self-generated. This failure would lead the patients to interpret internal speech as coming from external sources, thus producing auditory hallucinations. In addition, the brains of patients with schizophrenia appear to suffer tissue loss in certain regions. In early 2004, some German researchers reported a direct correlation between the severity of auditory hallucinations in patients with schizophrenia and the amount of brain tissue that had been lost from the primary auditory cortex.

Diagnosis

The differential diagnosis of hallucinations can be complicated, but in most cases taking the patient's medical history will help the doctor narrow the list of possible diagnoses. If the patient has been taken to a hospital emergency room, the doctor may ask those who accompanied the patient for information. The doctor may also need to perform a medical evaluation before a psychiatric assessment of the hallucinations can be made. The medical evaluation may include laboratory tests and imaging studies as well as a physical examination, depending on the patient's other symptoms. If it is suspected that the patient is suffering from delirium, dementia, or a psychotic disorder, the doctor may assess the patient's mental status by using a standard instrument known as the mini-mental status examination (MMSE) or the Folstein (after the clinician who devised it). The MMSE yields a total score based on the patient's appearance, mood, cognitive skills, thought content, judgment, and speech patterns. A score of 20 or lower usually indicates delirium, dementia, schizophrenia, or severe depression.

Hallucinations in elderly patients may require specialized evaluation because of the possibility of overlapping causes. The American Association for Geriatric Psychiatry lists hallucinations as an indication for consulting a geriatric psychiatrist. In addition, elderly patients should be routinely screened for visual or hearing impairments.

Treatment

Hallucinations are treated with regard to the underlying disorder. Depending on the disorder, treatment may involve antipsychotic, anticonvulsant, or antidepressant medications; psychotherapy; brain or ear surgery; or therapy for drug dependence. Hallucinations related to normal sleeping and waking are not a cause for concern.

Prognosis

The prognosis of hallucinations depends on the underlying cause or disorder.

BOOKS

Altman, Lawrence K., MD. Who Goes First? The Story of Self-Experimentation in Medicine. Berkeley, CA: University of California Press, 1998.

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

Beers, Mark H., MD. "Behavior Disorders in Dementia." The Merck Manual of Geriatrics, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

"Drug Use and Dependence." The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

Matthiessen, Peter. The Snow Leopard. New York: Penguin Books USA, 1987.

"Psychiatric Emergencies." The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.

"Schizophrenia and Related Disorders." Section 15, Chapter 193 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2002.