Learn what may cause this change in mental abilities. Symptoms develop fast and include confusion and being unaware of surroundings.
Update Date: 18.04.2026
Delirium is a serious change in mental abilities. It causes people to become confused and unaware of their surroundings. This condition comes on fast. Typically, symptoms appear over a few hours or a few days.
A number of medical concerns may cause delirium, including having a serious or long illness. Delirium might be due to not having enough of an important nutrient in the body, such as having low sodium levels. Delirium also may be caused by some medicines, infection, surgery, or substance use or withdrawal, including alcohol and other drugs.
Symptoms of delirium can look like symptoms of dementia. To diagnose delirium, healthcare professionals may rely on input from family members, caregivers or other people familiar with the person's typical abilities.
Symptoms of delirium usually begin over a few hours or a few days. They typically happen along with another medical condition or in addition to other symptoms, such as pain or fever. Delirium symptoms often come and go. There may be times when symptoms disappear. Symptoms tend to be worse in dark or unfamiliar settings, such as at night or in a hospital room.
The main symptoms of delirium fall into several broad categories.
This may lead to:
This may appear as:
These may include:
There are three types of delirium:
Delirium and dementia may be hard to tell apart. Some people may have both. Someone with dementia has a slow decline of memory and other thinking skills. This is 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 happens in people with dementia. But having an episode of delirium doesn't always mean a person has dementia. Tests for and a diagnosis of dementia shouldn't be made during a delirium episode because test results may not be accurate.
Some differences between the symptoms of delirium and dementia include:
If a family member, friend or someone you support shows symptoms of delirium, talk to that person's healthcare professional as soon as possible, especially if there are symptoms of an infection, such as a cough or urinary concerns. Your input about a person's symptoms, typical thinking and other abilities will be important for a diagnosis. Telling the team about changes you've seen also can help find the cause of delirium.
If you notice symptoms of delirium in someone in the hospital or in a long-term care center, tell the nursing staff or another member of the healthcare team right away. Older adults who are in the hospital, especially those in intensive care, and people living in a long-term care center are at higher risk of delirium.
Delirium happens when signals in the brain aren't sent and received correctly.
Delirium may have a single cause or more than one cause. For example, a medical condition along with the side effects of a medicine could cause delirium. Sometimes no cause can be found.
Possible causes of delirium include:
Some medicines taken alone or taken together can trigger delirium. These include medicines that treat:
Any condition that leads to a hospital stay raises the risk of delirium. This is especially true when someone is recovering from surgery or is in intensive care. Delirium is more common in older adults who are in the hospital and in people who live in long-term care centers.
Examples of other conditions that may raise the risk of delirium include:
Delirium may lead to other health concerns, called complications. The complications people with delirium develop tend to depend on how quickly they recover from delirium. The condition may last only a few hours, or it may last several days, weeks or months. If the causes of delirium are successfully treated, recovery time often is shorter.
Recovery depends in part on how healthy a person was before delirium started. For example, people with dementia may have 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 get back the thinking skills and other mental skills that they had before an episode of delirium. Delirium in seriously ill people is more likely to lead to:
Some steps can help prevent delirium or make it less serious if it happens. Those steps include:
Taking these steps may be hard when someone is in the hospital. That's because hospital stays often include room changes, invasive procedures, loud noises and poor lighting. And lack of natural light and lack of sleep can make confusion worse. If you're worried that someone in the hospital may be at risk of delirium, talk to a member of the healthcare team.
A delirium diagnosis is based on recent medical history and physical and mental tests. An exam may include:
Treating delirium first involves addressing anything that could have caused delirium. That may include stopping some medicines, treating an infection or treating a lack of nutrients in the body. After that, treatment of delirium focuses on creating the best setting for healing the body and calming the brain. That may include a range of measures.
The goal of supportive care is to prevent a person from developing other health issues as a result of delirium. To do that, the healthcare team likely will take the following steps:
If you're a family member or caregiver of someone who has delirium, talk with a member of the healthcare team about medicines that may trigger symptoms. The person with delirium may need to stop taking those medicines or take them at a lower dose.
Sometimes pain may cause delirium. In those situations, medicine may be prescribed to manage pain. Other 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 go away, the medicines are usually stopped or are given in lower doses.
If you're a family member or caregiver of someone who is at risk of delirium, you can take steps to help prevent an episode of delirium. If you take care of someone who is recovering from delirium, these steps also can help improve the person's health and prevent another episode.
To help get a good night's sleep:
To help the person remain calm and aware of the surroundings:
To help prevent medical issues:
Caring for a person with delirium can be hard and exhausting. Take care of yourself too.
If you're a family member or primary caregiver of a person with delirium, you'll likely play a role in making an appointment or giving information to the healthcare team. Here's some information to help you get ready for the appointment and know what to expect.
Before the appointment, make a list of:
A healthcare professional is likely to ask questions about the person with delirium. The questions may include:
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