Healthdirect Free Australian health advice you can count on.

Medical problem? Call 1800 022 222. If you need urgent medical help, call triple zero immediately

healthdirect Australia is a free service where you can talk to a nurse or doctor who can help you know what to do.

beginning of content

Delirium

9-minute read

Key facts

  • Delirium is a sudden change in the way you think and behave.
  • Delirium is often caused by changes in your health, such as an infection or a medicine change.
  • You have a higher chance of delirium if you have had it before, have dementia or recently had surgery.
  • If you're in hospital and at risk, your doctor will provide care to prevent delirium.
  • Delirium can cause complications, such as injury from falls, dehydration, malnutrition and pressure sores.

What is delirium?

Delirium is when you have a sudden change in the way you think or behave. It is often a symptom of a serious illness.

Delirium can develop quickly and lasts for a few days. It is common in older people, but it can happen at any age.

If you have delirium when in hospital, you may be at higher risk of medical complications.

What are the symptoms of delirium?

Delirium can cause a range of symptoms, including sudden confusion and changes in behaviour. You may notice that someone with delirium:

  • is confused or forgetful
  • doesn't know the time or where they are
  • acts differently from usual
  • is unsettled, sleepy or has changes in their sleep pattern
  • feels scared, upset, irritable, angry or sad
  • sees things that are not there (hallucinations)
  • loses control of bladder or bowels (incontinence)

These symptoms can start suddenly, over a few hours or days. They can last for a few days or weeks.

Delirium, dementia and depression

Delirium, dementia and depression can seem similar, but they are different.

  • Dementia is a condition where a person's memory, thinking, understanding or judgement gets worse slowly over time.
  • Depression means having a low mood for at least 2 weeks.
  • Delirium occurs suddenly. Symptom of delirium can change throughout the day.

CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

When should I call an ambulance or go to the emergency department?

If you are worried someone has signs of delirium, call triple zero (000) and ask for an ambulance or take them to the emergency department.

Delirium is a medical emergency. If you have delirium, you are at a high risk of harming yourself or someone else. The cause of your delirium needs to be identified and treated.

If you notice a sudden change in someone's mental or physical condition, it is important to tell a doctor.

What should I do while waiting for an ambulance?

While waiting for an ambulance, keep the person safe and try to keep them calm. Provide paramedics with important details about their:

  • medical history
  • medicines
  • recent changes in behaviour

FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services.

What causes delirium?

Delirium is often caused by changes in your health, such as a physical illness or infection. It can also result from a change in your prescription medicines.

Other causes for delirium include:

It is not always possible to find the cause of delirium.

Who is at risk of delirium?

You are at a higher risk of delirium if you:

  • are aged over 65 years, or aged over 45 years for Aboriginal and/or Torres Strait Islander people
  • take multiple medicines or have had recent changes to medicines
  • have had recent surgery — such as hip or heart surgery
  • are living with depression
  • are sick or frail
  • have poor eyesight or hearing loss
  • have a cognitive impairment — such as dementia, intellectual disability or brain injury
  • have had delirium before

How is delirium diagnosed?

Your doctor can diagnose delirium by asking you or people with you about any sudden changes in your behaviour or thinking. Your doctor may check you a few times throughout the day before making a diagnosis.

To find the cause, your doctor may:

ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How is delirium treated?

Treatment for delirium focuses on finding and addressing the cause and providing supportive care.

Your doctor may treat delirium by:

  • changing your prescription medicines
  • giving you intravenous fluids
  • prescribing antibiotics if you have an infection
  • prescribing antipsychotic medicines when other methods to manage delirium don't work

Supportive care

It can be reassuring for someone with delirium to see familiar faces. You may be encouraged to stay with your loved one if they are in hospital and have delirium.

Here are some tips to help and care for someone with delirium:

  • Speak slowly and clearly.
  • Identify yourself and the person by name.
  • Avoid arguing with them and remind them of the time and date and where they are.
  • Help them put on their hearing aids and glasses.
  • Let them walk if they want, ensuring they are safe from falling and hazards.
  • Bring them familiar items, such as photos, clothes or favourite music.
  • Share personal information with staff that may help calm and orient the person. This can be names of family and friends, hobbies and significant events.

What are the complications of delirium?

Delirium can lead to several complications, including:

Can delirium be prevented?

Delirium can be prevented with proper care. If you are at risk, your doctor may:

  • check your medicines and adjust those that may increase your risk
  • encourage you to eat and drink to stay hydrated and nourished
  • help you stay active
  • If you are in hospital, your healthcare team can try to prevent delirium by:
  • developing a delirium prevention plan with you and your family or carer
  • communicating clearly
  • encouraging you to eat and drink to stay hydrated and nourished
  • managing your pain effectively
  • regularly reminding you of the place, time and date
  • helping you wear your glasses and hearing aids
  • helping you get out of bed for meals or after a procedure

Resources and support

Do you prefer to read in languages other than English?

Looking for information for Aboriginal and/or Torres Strait Islander people?

Learn more here about the development and quality assurance of healthdirect content.

Last reviewed: September 2024


Back To Top

Need more information?

These trusted information partners have more on this topic.

Top results

Delirium

This brochure provides information for people who are at risk of, or have experienced delirium, and for their families and carers.

Read more on ACI - Agency for Clinical Innovation website

Delirium | Dementia Australia

Delirium is a state of severe confusion. Learn why delirium happens, and what you can do to help to manage it.

Read more on Dementia Australia website

Memories, hallucinations and delirium - My Life After ICU

Looking back at your time in ICU, you may have some memories of experiences of things that did not make sense when you were very ill

Read more on Australian and New Zealand Intensive Care Society website

Cognitive impairment and COVID-19 | Australian Commission on Safety and Quality in Health Care

During COVID-19, people with cognitive impairment may be further disoriented by the use of personal protective equipment (PPE) and find instructions such as social distancing hard to follow.

Read more on Australian Commission on Safety and Quality in Health Care website

Brain fog and concentration issues - My Life After ICU

After leaving the ICU, 30% – 80% of patients may have problems with things like sleeping, concentration, memory and mood

Read more on Australian and New Zealand Intensive Care Society website

Healthdirect 24hr 7 days a week hotline

24 hour health advice you can count on

1800 022 222

Government Accredited with over 140 information partners

We are a government-funded service, providing quality, approved health information and advice

Australian Government, health department logo ACT Government logo New South Wales government, health department logo Northen Territory Government logo Queensland Government logo Government of South Australia, health department logo Tasmanian government logo Victorian government logo Government of Western Australia, health department logo

Healthdirect Australia acknowledges the Traditional Owners of Country throughout Australia and their continuing connection to land, sea and community. We pay our respects to the Traditional Owners and to Elders both past and present.