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Medically reviewed by Last updated on Oct 14, 2022.


Delirium is a serious change in mental abilities. It results in confused thinking and a lack of awareness of someone's surroundings. The disorder usually comes on fast — within hours or a few days.

Delirium can often be traced to one or more factors. Factors may include a severe or long illness or an imbalance in the body, such as low sodium. The disorder also may be caused by certain medicines, infection, surgery, or alcohol or drug use or withdrawal.

Symptoms of delirium are sometimes confused with symptoms of dementia. Health care providers may rely on input from a family member or caregiver to diagnose the disorder.


Symptoms of delirium usually begin over a few hours or a few days. They typically occur with a medical problem. Symptoms often come and go during the day. There may be periods of no symptoms. Symptoms tend to be worse at night when it's dark and things look less familiar. They also tend to be worse in settings that aren't familiar, such as in a hospital.

Primary symptoms include the following.

Reduced awareness of surroundings

This may result in:

Poor thinking skills

This may appear as:

Behavior and emotional changes

These may include:

Types of delirium

Experts have identified three types:

Delirium and dementia

Delirium and dementia may be hard to tell apart, and a person may have both. Someone with dementia has a gradual decline of memory and other thinking skills due to damage or loss of brain cells. The most common cause of dementia is Alzheimer's disease, which comes on slowly over months or years.

Delirium often occurs in people with dementia. However, episodes of delirium don't always mean a person has dementia. Tests for dementia shouldn't be done during a delirium episode because the results could be misleading.

Some differences between the symptoms of delirium and dementia include:

When to see a doctor

If a relative, friend or someone in your care shows symptoms of delirium, talk to the person's health care provider. Your input about symptoms, typical thinking and usual abilities will be important for a diagnosis. It also can help the provider find the cause of the disorder.

If you notice symptoms in someone in the hospital or nursing home, report your concerns to the nursing staff or health care provider. The symptoms may not have been observed. Older people who are in the hospital or are living in a long-term care center are at risk of delirium.


Delirium occurs when signals in the brain aren't sent and received properly.

The disorder may have a single cause or more than one cause. For example, a medical condition combined with the side effects of a medicine could cause delirium. Sometimes no cause can be found. Possible causes include:

Some medicines taken alone or taken in combination can trigger delirium. These include medicines that treat:

Risk factors

Any condition that results in a hospital stay increases the risk of delirium. This is mostly true when someone is recovering from surgery or is put in intensive care. Delirium is more common in older adults and in people who live in nursing homes.

Examples of other conditions that may increase the risk of delirium include:


Delirium may last only a few hours or as long as several weeks or months. If the causes are addressed, the recovery time is often shorter.

Recovery depends to some extent on the health and mental status before symptoms began. People with dementia, for example, may experience an overall decline in memory and thinking skills after a delirium episode. People in better health are more likely to fully recover.

People with other serious, long-lasting or terminal illnesses may not regain the thinking skills or function that they had before the onset of delirium. Delirium in seriously ill people is more likely to lead to:


The best way to prevent delirium is to target risk factors that might trigger an episode. Hospital settings present a special challenge. Hospital stays often involve room changes, invasive procedures, loud noises and poor lighting. Lack of natural light and lack of sleep can make confusion worse.

Some steps can help prevent or reduce the severity of delirium. To do this, promote good sleep habits, help the person remain calm and well-oriented, and help prevent medical problems or other complications. Also avoid medicines used for sleep, such as diphenhydramine (Benadryl Allergy, Unisom, others).


A health care provider can diagnose delirium based on medical history and tests of mental status. The provider also will consider factors that may have caused the disorder. An exam may include:


The first goal of delirium treatment is to address any causes or triggers. That may include stopping certain medicines, treating an infection or treating an imbalance in the body. Treatment then focuses on creating the best setting for healing the body and calming the brain.

Supportive care

Supportive care aims to prevent complications. Here are steps to take:


If you're a family member or caregiver of someone who has delirium, talk with the health care provider about medicines that may trigger the symptoms. The provider may suggest that the person avoid taking those medicines or that a lower dose is given. Certain medicines may be needed to control pain that's causing delirium.

Other types of medicines may help calm a person who is agitated or confused. Or medicines may be needed if the person is showing distrust of others, is fearful or is seeing things that others don't see. These medicines may be needed when symptoms:

When symptoms resolve, the medicines are usually stopped or are given in lower doses.

Coping and support

If you're a relative or caregiver of someone who is at risk of delirium, you can take steps to prevent an episode. If you take care of someone who is recovering from delirium, these steps can help improve the person's health and prevent another episode.

Promote good sleep habits

To promote good sleep habits:

Promote calmness and orientation

To help the person remain calm and aware of their surroundings:

Prevent complicating problems

To help prevent medical problems:

Caring for the caregiver

Caring for a person with delirium can be scary and exhausting. Take care of yourself too.

Organizations that may provide helpful information include the Caregiver Action Network and the National Institute on Aging.

Preparing for an appointment

If you're the relative or primary caregiver of a person with delirium, you'll likely play a role in making an appointment or providing information to the health care provider. Here's some information to help you get ready for the appointment and know what to expect.

What you can do

Before the appointment, make a list of:

What to expect from the doctor

A health care provider is likely to ask several questions about the person with delirium. These may include:

The provider may ask additional questions based on your responses and the person's symptoms and needs. Preparing for these questions helps you make the most of your time with a provider.

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