For families and carers

New confusion has a name: delirium

Delirium is a sudden change in a person’s thinking, memory or alertness, usually caused by an illness, an injury, surgery or medicines. It affects 1 in 4 older people in hospital. Many families have never heard its name.

Scope of this website. This site focuses mainly on delirium in older people outside intensive care. Much of it is relevant in an ICU, but Vanderbilt has more specific ICU information. It does not cover paediatric delirium; the Resources page links to specialist information for babies, children and young people.

Written by Professor Alasdair MacLullich, Professor of Geriatric Medicine at the University of Edinburgh.

Is this delirium? The common signs

Delirium appears over hours or days. The person is different from their normal self. You might notice:

Sudden confusion

Losing track of where they are, or what day or time it is. Clearly more muddled than normal.

Trouble paying attention

Conversations keep falling apart. They drift off mid-sentence or seem not to hear you.

Unusual drowsiness

Much sleepier than usual, sleeping through visits, or slow to respond. If they are hard to wake or barely responding, get emergency help now.

Restlessness or agitation

Pacing, fiddling, pulling at drips, sometimes fear or anger.

New suspicion, or seeing things

Believing others mean harm, or seeing people or animals that are not there.

Symptoms that come and go

Settled in the morning, lost by teatime. Evenings and nights are often worse.

New sudden confusion can be caused by serious illness and needs medical assessment now. Contact the urgent or emergency medical service where the person is. In England, call 999 or go to A&E. In Scotland, contact the GP urgently if open; otherwise phone NHS 24 on 111. Outside the UK, follow local health-service guidance. If the person is hard to wake, struggling to breathe, has signs of a stroke, has a seizure or head injury, or is deteriorating rapidly, call the local emergency number immediately (999 in the UK). Do not wait to see if it settles. What to do now.

Delirium is not dementia

Dementia builds slowly, over months and years. Delirium arrives in hours or days, and it usually improves once its causes are found and treated. The two conditions are often mistaken for each other, including by professionals.

If someone who already has dementia suddenly gets much worse, treat the change as possible delirium.

See the differences at a glance

Dementia changes over months to years years Delirium changes over hours to days days

Someone to talk to

These UK helplines can talk through what is happening. You do not need a dementia diagnosis in the family to phone them. Outside the UK, look for an equivalent dementia, carers’ or older people’s service in your country.

More helplines and what each one can help with

The book

A family guide to delirium, coming soon

Delirium (Acute Confusion): A Family Guide to Sudden Changes in Thinking and Memory is a detailed, book-length guide to delirium written for families and carers. It is by Professor Alasdair MacLullich and Dr Sharmella Summan, who experienced severe delirium herself while seriously unwell in intensive care.

The book covers the causes and treatment of delirium, what the experience is like from the inside, how to raise concerns with staff, recovery, and the relationship between delirium and dementia. This website gives a short overview. The book covers each subject in more detail.

Book details at the4at.com

Printable guides

One page each. Print them for the ward, the kitchen drawer, or a relative who does not use the internet.

Delirium action guide

The signs, who to contact, and when to seek emergency help.

Download the Delirium action guide (PDF)

Telling the team

The six things doctors and nurses need to hear from you.

Download Telling the team (PDF)

Helping at the bedside

Simple things that reduce fear and confusion, hour to hour.

Download Helping at the bedside (PDF)

Delirium or dementia?

The differences at a glance, as a one-page table.

Download Delirium or dementia? (PDF)

Raising concerns with staff

The words to use with staff, on one printable page.

Download Raising concerns with staff (PDF)
Delirium Support

Written by Professor Alasdair MacLullich

ORCID 0000-0003-3159-9370 · University of Edinburgh profile · the4at.com

Facebook · X (Twitter) · LinkedIn · Threads

Support helplines in the UK: Dementia UK 0800 888 6678 · Alzheimer’s Society 0333 150 3456 · Age UK 0800 678 1602 · Carers UK 0808 808 7777. The 0800 and 0808 numbers are free to call; the 0333 number is charged at the standard rate. Outside the UK, contact an equivalent dementia, older people’s or carers’ organisation in your country. These helplines are not emergency services.

Delirium Support is an independent educational website. It is not an official NHS or University of Edinburgh site, and neither organisation is responsible for its content. It gives general information about delirium for education. It is not medical advice about an individual, and it is not a substitute for the clinicians looking after your relative. New sudden confusion needs medical assessment now. Contact the urgent or emergency medical service where the person is. In England, call 999 or go to A&E. In Scotland, contact the GP urgently if open; otherwise phone NHS 24 on 111. Outside the UK, follow local health-service guidance. If the person is hard to wake, struggling to breathe, has signs of a stroke, has a seizure or head injury, or is deteriorating rapidly, call the local emergency number immediately (999 in the UK). Do not wait to see if it settles.

© 2026 Alasdair MacLullich · Content licensed under CC BY 4.0 · About · Privacy · Pages last reviewed July 2026.