Delirium (sudden confusion)

Delirium (sudden confusion) usually affects people’s brains for a short time. It is a common condition. Up to 1 in 3 people admitted to hospital become delirious at some time during their stay.

People with delirium might be confused or agitated and act differently than usual. They can seem alert or drowsy (sleepy). They might also have memory problems or see and hear things that are not there.

Depending on how bad the delirium is, a person may need to go into hospital for treatment and management. For others, delirium can be treated at home.

Delirium can be a frightening condition for those who have it, together with their family and carers. Not everyone remembers delirium, but those that do may find the memories distressing.

It is not always possible to prevent delirium. However, if you're at risk of delirium, there are some things that you can do to reduce the risk yourself. These things can also help you to recover from delirium when you're in hospital.

Family members and carers have an important role. They can help to manage delirium in hospital or at home.

Causes of delirium

Delirium can have different causes. We may need to do medical tests to help decide what treatment is needed.

As you get older, you are more likely to have delirium. People who are over 80 years old and have been diagnosed with some type of dementia are particularly at risk. However, delirium can happen in younger people as well, especially if they are critically ill or after surgery.

Symptoms of delirium

There are various symptoms that can help a family member or carer to recognise delirium. If you notice any of these symptoms, please tell a doctor or nurse.

Family members and carers are often the first to notice small changes. We've included quotes from family members describing behaviour and symptoms of delirium. This might help you to recognise symptoms.


Some people may not know where they are or what time of day it is.

“My wife has mild dementia, but we usually manage fine at home. She still recognises most of our neighbours and friends. When she was in hospital, though, she did not even recognise me or our daughter.”

Unusual thoughts

Some people may become paranoid (suspicious) and mistrustful of the people around them. These thoughts can sometimes become distressing.

“After her hip operation, my mother became very confused and aggressive. She kept pulling out her drip and shouting at the nurses. It was a shock as she is usually so polite.”

Poor concentration

Some people may find it difficult to follow what others say to them.

Memory loss

Some people may have memory loss. Problems with short-term memory are particularly common. People with delirium may not remember what has happened or where they are.


Some people become drowsy or sleepy.

“We can often tell that my father is getting a urinary infection because he starts to get slower and becomes quiet and withdrawn. He also sleeps much more.”

Agitation or restlessness

Some people may shout or become aggressive. They may get out of bed unexpectedly, which increases the risk of falling.

“My father became very confused. He was sleepy at times, and agitated and restless at other times. The community nurses gave him medicine to help control his symptoms.”


Some people may see and hear things that are not there.

Sudden changes

Delirium can change within the space of a day. People may be delirious, then appear normal and then be delirious again. Symptoms are often worse at night.

“The nurses told me that my grandmother had been up all night, wandering around the ward and trying to leave. However, when I visit her on the ward in the daytime, she is nice and quiet and seems OK.”

Physical changes

Some people may have changes in their appetite, movement (mobility) or swallowing.


Some people may become unsteady and more likely to fall.

When you think someone is delirious

In hospital, you can tell the nurse or doctor looking after the person about the symptoms you have noticed. At home, you can talk to a GP.

The person may not know that anything is wrong. Family and friends are often the first to notice small changes.

Treatment for delirium

Some people with delirium need to come into hospital to manage the condition or what is causing it. They might also be in hospital for another reason and get delirium during their stay.

The doctors and nurses test for and manage any causes of delirium that can be treated. Examples are:

  • infections
  • abnormal blood results
  • constipation (finding it hard to poo)
  • not being able to pee
  • dehydration
  • the side effects of different medicines

Sometimes, we give the person with delirium calming or sedating medicines. We use these medicines if the person is still distressed or unsafe after we have tried other ways to keep them calm.

How long delirium lasts

Delirium usually gets better. In 6 out of 10 people (60%), the symptoms disappear within 6 days. Others may have some symptoms for longer. About 1 in 20 people (5%) may still have delirium more than a month after they first had symptoms.

Delirium is always a serious condition. Although many people make a full recovery, some people never get back to how they were completely. This may apply if you:

  • have dementia
  • have had delirium before
  • live in a care home (because it is likely that you already have health problems)

Leaving hospital after delirium

When a person leaves hospital after delirium, they may need more support than usual. They may be at higher risk of falls and need some changes in the home to make sure that their environment is safe.

If you think that extra support may be needed, speak to the doctors and nurses on the ward before your loved one goes home. There are many ways that we can support people who leave hospital after delirium.

We try to make sure that people get the right level of support when they leave hospital. This includes rehabilitation to improve, restore and maintain their everyday skills and mobility.

If you are concerned about anything after going home, please speak to staff at your outpatient appointment or your GP.

Useful sources of information

Alzheimer’s Society gives advice and support on all types of dementia.

Phone: 0333 150 3456 or visit www.alzheimers.org.uk

Carers UK gives information and support for carers.

Phone: 0808 808 7777 or visit www.carersuk.org

Age UK gives advice, information and support for older people.

Phone: 0800 678 1602 or visit www.ageuk.org.uk

Resource number: 3532/VER5
Last reviewed: December 2023
Next review: December 2026

Contact us

If you have any questions or concerns about delirium, speak to a nurse or doctor. If the person with delirium is not in hospital, speak to their GP or community nurses.

You can also contact the delirium and dementia team.

Phone: 020 7188 7188 extension 53293. Monday to Friday, 9am to 5pm.

Out of hours, please call 020 7188 7188 and ask for the site nurse practitioner on duty.

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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