Delirium is the sudden onset of widespread generalized confusion. It is a serious condition that can lead to death if not treated immediately. The cause is presumed to be interference in the neurotransmitters * in the brain. When a situation prevents the neurotransmitters from sending out vital instructions from the brain to the rest of the body, there is no way to make sense of the information coming from the senses, which is when general confusion sets in. In this condition, an individual cannot even recognize or perceive familiar objects and situations accurately.

Joey's Story

Joey was hurrying down the hall of his high school, heading to his algebra class. He noticed a man standing in the hallway watching the students go past. The man seemed very interesting; his face looked like someone from Joey's history book, but his clothes were modern. Joey was so fascinated with the man that he went up to him and asked, “Who are you?”

“Where are you supposed to be going?” The man asked sternly.

Joey felt the man did not want to be bothered, but as he turned away from the man, he realized he did not know where he was going. “I guess I'm going to lunch,” Joey muttered.

“Lunch was hours ago,” the man exclaimed.

“What am I doing in school? How did I get here?” Joey asked.

“Joey, are you OK? Tell me that you know me. I'm Principal Fletcher,” the man said. “Joey, come on. Tell me you're joking.”

Principal Fletcher thought Joey was acting like students who used psychoactive * drugs, but Joey was not the type. What kind of drug could Joey have taken? Then Principal Fletcher remembered signing Joey into school late this morning because Joey had been to a doctor's appointment. If the doctor had prescribed a new drug, Joey could be experiencing delirium.

What Is Delirium?

Delirium occurs when normal signals in the brain become impaired, most likely caused by a combination of factors. Its onset is sudden and is exhibited by severely impaired thinking. Dehydration, fever, multiple medications, including some allergy medications, and drug and alcohol use are among the common causes of delirium. Old age and dementia are also common causes.

Delirium is a symptom of some disease or medical disorder. People with delirium have trouble with simple reasoning and speaking. Delirium characteristically involves rapid and frequent changes between mental states. An individual may start off agitated and then become extremely calm, only to go right back to being agitated. Doctors who deal most often with delirium work with emergency room and cancer patients.

There are many causes of delirium, but the psychological * explanation for the symptoms is dysfunction in critical areas of the brain and interference of essential neurotransmitters. The two main areas of the brain that influence the onset of delirium symptoms are the prefrontal cortex (the part of the brain responsible for decision making) and the parietal areas (the part of the brain responsible for perception). The main neurotransmitters that are disrupted and lead to delirium are acetylcholine * , serotonin * , and dopamine * . Acetylcholine is important for learning and memory. Serotonin affects moods and arousal. Dopamine contributes to attention and emotion.

How Common Is Delirium?

Delirium can affect people of all ages; however, it is most common among the elderly. There are more cases of delirium in males than in females. Delirium is the cause in about 20 percent of all people admitted to the hospital. Surprisingly, delirium goes unreported in as many as two-thirds of all patients. Most of these unreported cases are associated with patients whose main symptom of delirium is abnormal calmness. Critically ill patients may be monitored regularly for delirium.

Is Delirium Contagious?

As a symptom of another underlying problem, delirium in and of itself is not contagioius. However, if the delirium is caused by a high fever associated with infection, the infection that caused the fever may be very contagious.

How Do People Know They Have Delirium?

The key symptom of delirium is sudden, acute confusion. Detailed signs of delirium can be deduced by reviewing the brain functions that are disturbed at the time of the onset. Because the prefrontal cortex is not working correctly, people are not able to make even the smallest decisions. Hallucinations are common because individuals' perception has ceased operating. With acetylcholine dispersed or blocked, even the most common and essential thoughts and memories are unavailable. The inaction of serotonin brings on wide mood swings as well as sleep disorders. Emotion is inappropriate and attention is weak as a result of problems with dopamine levels in the brain. People with delirium may be agitated inappropriately or abnormally calm.

How Do Doctors Diagnose and Treat Delirium?

Diagnosis * or acute, sudden delirium.


Treatment for delirium focuses on addressing the underlying cause. When the underlying cause is identified and treated, efforts are made to relieve the delirium. Drugs are not the first choice in treating delirium. However, some drugs can help if patients are hurting themselves or others, or are not responding well to nonmedicinal treatments. Antipsychotic drugs * may be prescribed; they are used primarily for their calming effects. The use of drugs to treat delirium, however, can have adverse or even paradoxical effects that lead the patient to become even more agitated and delusional.

Nonmedicinal treatments include making the patient's environment as familiar and calming as possible. The patient's family should bring personal objects from home to make the hospital room seem more familiar. The hospital staff interacting with the patient should be limited in number so the patient does not get confused by seeing too many new faces. Also, whenever possible, the patient should have a private room, be informed regularly about his or her condition, and be provided with mentally challenging activities.


Delirium is often confused with dementia. The two disorders share symptoms, but one of the key components of delirium is the patient's struggle to understand his or her surroundings, which is not necessarily present in people with dementia. Those with delirium and dementia both have a hard time understanding what is being told to them; however, delirium involves general confusion, whereas dementia involves confusion specific to the processing of new information and memory tasks. Delirium is a symptom of a serious underlying disorder; dementia is a disorder with a collection of symptoms, one of which is delirium. Delirium is expected to be short term and reversible, whereas dementia involves a slow, steady decline in mental functioning.

Can Delirium Be Prevented?

See also Creutzfeldt-Jakob Disease • Dementia • Fever • Mercury Poisoning



Health in Aging Foundation. “Aging & Health A–Z: Delirium.” (accessed December 2, 2015).

Lithwick, Dahlia. “Dying of Excitement: Police Often Blame Suspects' Deaths on ‘Excited Delirium.’ Is That a Diagnosis or a Cover-Up?” Slate, June 11, 2015. (accessed December 2, 2015).


American Delirium Society. 1183 University Dr., Suite 105–106, Burlington, NC 27215. Telephone: 410-955-2434. Website: (accessed December 2, 2015).

ICU Delirium and Cognitive Impairment Study Group. 1215 21st Ave. S, 6th Floor, Medical Center East, Suite 6000, Nashville, TN 37232. Website: (accessed December 2, 2015).

* neurotransmitters (nur-otrans- MIH-terz) are chemical substances that transmit nerve impulses, or messages, throughout the brain and nervous system. They are involved in the control of thought, movement, and other body functions.

* psychoactive (sy-ko-AK-tiv) refers to affecting a person's mood, behavior, perceptions, or consciousness.

* psychological (SI-ko-LOJ-i-kal) refers to mental processes, including thoughts, feelings, and emotions.

* acetylcholine (uh-SEET-l-kohleen) is a neurotransmitter in the brain that functions to excite nerve cells.

* serotonin (ser-o-TO-nin) is a neurotransmitter, a substance that helps transmit information from one nerve cell to another in the brain. It is associated with feelings of well-being.

* dopamine (DOE-puh-meen) is a neurotransmitter in the brain that controls motor activity (movement).

* dementia (dih-MEN-shuh) is a loss of mental abilities, including memory, understanding, and judgment.

* antipsychotic drugs are medications that counteract or reduce the symptoms of a severe mental disorder, such as schizophrenia.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)