Confusion and Delirium
Confusion and delirium affect how a person thinks and behaves. When someone is confused or delirious, they can't think clearly. They might not behave like they usually do. Confusion and delirium usually only last a short time, but they can be a sign of something more serious.
What are confusion and delirium?
Confusion means a person can’t think clearly. People who are confused may think more slowly. They can have trouble focusing and understanding what’s going on around them. Confusion might last for a short time or can continue for longer.
Delirium is a more severe kind of confusion. It affects memory and thinking. It changes the way a person behaves and sees the world around them. Delirium comes on quickly and can be worse at night.
Delirium can often get better when the cause is found and treated. But sometimes it does not go away, especially in people who are very sick or near the end of life.
There are 3 types of delirium:
- Hypoactive: The person may act tired or sleepy. This is the most common type. It can be easy to miss or mistake for being sad or “not themselves.”
- Hyperactive: The person may seem to be restless, upset, or agitated.
- Mixed: At different times, the person may go from having either hypoactive or hyperactive delirium.
What causes confusion and delirium?
Many things can cause confusion and delirium in people with cancer. Often there is more than one cause.
Cancer-related factors that can lead to confusion and delirium are:
- Cancer, especially if it is in the brain or the fluid around the brain
- Cancer treatments, such as some types of chemotherapy and immunotherapy, radiation to the brain, surgery, and stem cell or bone marrow transplant
- Changes in blood chemistry, including electrolytes, high calcium or low blood sugar, magnesium, phosphorous, or sodium
- Infection or high fever
- Severe pain
- Not getting enough oxygen to the brain
- Low red blood cell counts (anemia)
Other medicines, health problems, or lifestyle factors that can lead to confusion or delirium:
- Some medicines, such as steroids, pain or sleep medicine, and those used to prevent or treat nausea, allergies, and loss of appetite
- Suddenly stopping alcohol or medicines for sleep or anxiety
- Problems with how organs like your liver or kidneys are working
- Not getting enough fluid (dehydration) or healthy food
- Not getting enough physical activity
Confusion and delirium also happen more often in people who:
- Are older
- Are in the hospital
- Have more advanced cancer
- Have trouble seeing or hearing
- Already have changes in their memory, thinking, or focus
- Have dementia or Parkinson’s disease or have had a stroke
Symptoms of confusion and delirium
The first symptom of confusion or delirium is often a sudden change in how alert a person is or how well they respond. Over a few hours or days, they might become very sleepy and out of touch with what’s going on around them. Or they might start to act very upset and nervous.
The person may have a hard time paying attention or following a conversation. They may not know where they are or what time it is. Most often, the person will not be aware of these changes, but their family members or cancer care team will notice them. Other symptoms might include the following.
Changes in speech and memory
- Long pauses or slurred words
- Forgetting what they were just doing
- Trouble paying attention or thinking clearly
- Not thinking clearly, not knowing where they are, or not knowing what time it is
Changes in mood and behavior
- Sudden changes in emotion, such as going from happy to upset
- Changes in personality
- Feeling anxious or sad
Changes in sleep and daily activities
- Being awake at night and sleepy during the day
- Needing more help with things like bathing and dressing
These symptoms can come and go. They can get worse at certain times, such as at night or if the person is in a new place.
Delirium may cause hallucinations. People may see, hear, smell, or feel things that are not there. But the hallucinations feel real to the person with delirium.
People with delirium may also have delusions, which means believing things that are not true. For instance, they might believe that someone is trying to harm them when that person is only trying to help.
Know how and when to get help
Call the cancer care team as soon as possible if your loved one:
- Becomes more confused
- Has any sudden changes in their ability to do routine tasks or care for themselves
- Becomes very restless
- Hurts themselves or someone else in some way
Make sure you know who to call on your loved one's cancer care team and how to reach them, including when the office or clinic is closed.
Treatment for confusion and delirium
Treatment for delirium and confusion depends on the cause. Many times, treating the cause will ease or get rid of delirium or confusion. The cancer care team will look for causes from any physical changes or medicines. They may also do tests, such as blood work, to try and find the cause.
There is no single medicine that cures delirium. The best care is often non-drug care. Sometimes your cancer care team may stop or change a medicine that is making things worse, such as calming or sleep medicines (benzodiazepines).
If a person is very upset or has scary hallucinations that put them at risk, the team may use medicine for a short time to keep them safe and calm.
Not all causes can be treated. This is often true when a person is near the end of life. In that case, keeping the person comfortable may be the best choice.
Tips for dealing with confusion and delirium
- Call your cancer care team right away or tell someone close to you if you feel confused or have other symptoms of delirium.
- Ask someone to stay with you to keep you safe.
- Try to stay in a room or other place where you feel comfortable and with people you know.
What caregivers can do
Caring for someone who is confused or has delirium can be hard. Changes in how they behave might make family and friends anxious or afraid.
The type of care that your loved one needs will depend on how confused they are and other symptoms they may have. Here are some things you can do to help keep your loved one safe and as comfortable as possible.
- Reassure the person who is confused that someone they know will stay with them.
- Set up a quiet room with good light and familiar people and objects.
- Play soft, soothing music when the person is in a room alone.
- Keep medicines out of reach between doses.
- When speaking to your loved one, focus their attention by gently touching them and standing in their line of sight. Let them know who you are. It might help to turn off background noise, like the TV or radio.
- Tell your loved one the date and time, and remind them where they are. It might help to place a clock and wall calendar where your loved one can see them.
- Label commonly used rooms and items with pictures. For example, put a picture of a toilet on the bathroom door and a picture of a flame over the stove.
- Open the curtains and keep the person active in the day.
- Keep the room quiet and dark at night.
- Use a night-light so that your loved one can see where they are if they wake during the night.
- You may need to help your loved one with physical care, such as bathing, going to the toilet, and preparing food.
- Make sure your loved one wears their glasses and hearing aids if they use them.
- When helping the person, tell them what you are going to do, and explain each step as you go along.
- Check to see that your loved one eats and drinks enough. They may forget to eat or may not be able to eat on their own.
- Encourage them to be as active as they can to keep up their strength. They may need someone with them to reduce the risk that they will fall.
- You or other family members may need to help make care decisions. It helps to have a primary caregiver who has been assigned to make decisions.
- Go to appointments with the person. Describe any signs of confusion or delirium to the care team. You can also help by taking notes and discussing the information given during appointments.
- Talk to the cancer care team about the medicines your loved one is taking. Some may make confusion or delirium worse. There also might be medicines that could help make your loved one more comfortable.
- If your loved one has hallucinations, ask the cancer care team what you can do to help manage them.
- Let the cancer care team know if you are having trouble managing your loved one’s care. They may have resources to help you and your loved one.
Confusion at the end of life
Many people have confusion and delirium at the end of their life. This is common and can be part of the dying process.
Some people say they can see or talk with loved ones who have died. These moments are often calm and comforting. They are not the same as delirium. If they do not upset the person, they do not need treatment. It helps to listen and let the person share them.
Delirium can also cause scary hallucinations. The person may see, hear, or feel things that are not there and feel afraid. If this happens, tell the care team. Medicine and support can help the person feel calm and safe.
There are medicines that can make a person with confusion or delirium more comfortable. The cancer care team may suggest sedation if a person is very agitated and not getting better with other treatments. Sedation can make the person who is dying more comfortable.
Deciding how to treat confusion or delirium depends on what the person with cancer would like. If possible, talk with your cancer care team about treatment options ahead of time. Think about putting health care wishes in writing.
What is terminal delirium?
Terminal delirium is a change in behavior in the last 1 to 2 weeks of life. It includes signs such as restlessness, confusion, fear, yelling, or seeing things that are not there. It is also called terminal restlessness or terminal agitation.
These changes are especially common in the final days of life. But it can be different for each person. These changes might happen due to dehydration, pain, trouble breathing, infections, fever, or side effects from cancer or medicines. Sometimes there is no clear cause.
Healthcare teams treat terminal delirium by giving medicines that ease confusion, pain, or worry. They will also treat other symptoms like trouble breathing and try to keep the room calm and quiet. In rare cases, doctors may use sedation to improve sleep when symptoms cannot be controlled in other ways.
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- References
Developed by the American Cancer Society medical and editorial content team with medical review and contribution by the American Society of Clinical Oncology (ASCO).
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Last Revised: October 27, 2026
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