delirium,dementia, and amnestic and other disorders

Delirium, dementia, and amnestic and other cognitive disorders




Dementia of the Alzheimer's Type, with early onset

Without behavioral disturbance

With behavioral disturbance

    • Dementia of the Alzheimer's Type, with late onset

      Without behavioral disturbance

      With behavioral disturbance

    • Vascular dementia

    • Uncomplicated

    • With delirium

    • With delusions

    • With depressed mood

  • Dementia due to HIV disease

  • Without behavioral disturbance

  • With behavioral disturbance

    • Dementia due to head trauma

    • Without behavioral disturbance

    • With behavioral disturbance

  • Dementia due to Parkinson's disease

    • Without behavioral disturbance

    • With behavioral disturbance

    Dementia due to Huntington's disease

    • Without behavioral disturbance

    • With behavioral disturbance

    • Dementia due to Pick's disease

    • Without behavioral disturbance

    • With behavioral disturbance

Dementia due to Creutzeldt-Jakob Disease

  • Without behavioral disturbance

  • With behavioral disturbance

Amnestic disorders

Amnestic disorder

Other cognitive disorders

Cognitive disorder


What is delirium?

Delirium is a state of mental confusion that can happen if you become medically unwell.  It is also known as an 'acute confusional state'.


Medical problems, surgery and medications can all cause delirium. It often starts suddenly and usually lifts when the condition causing it gets better. It can be frightening – not only for the person who is unwell, but also for those around him or her.

How is delirium treated?

If someone suddenly becomes confused, they need to see a doctor urgently. The person with delirium may be too confused to describe what has happened to them, so it's important that the doctor can talk to someone who knows the patient well.


To treat delirium, you need to treat the cause.  For example, an infection may be treated with antibiotics.


Can sedative medication (tranquillisers) help?

Sedatives can make delirium worse, so should only be used in a few situations:

  • When someone who drinks a lot of alcohol stops suddenly, they will need a regular dose of a sedative medication (benzodiazepines) that is reduced over several days. This will stop withdrawal symptoms, but should be done under close medical supervision.
  • To calm someone enough to have investigations or treatment.
  • To stop someone endangering themselves or other people.
  • When someone is very agitated or anxious.
  • When someone is seeing or hearing things that are not there.

Low doses of antipsychotic medication should be given to help with frightening hallucinations or beliefs that people are trying to harm you.

Any sedative medication should be given in the lowest possible dose for the shortest time possible.

How can I help someone with delirium?

You can help someone with delirium feel calmer and more in control if you:

  • Stay calm.
  • Talk to them in short, simple sentences. Check that they have understood you. Repeat things if necessary.
  • Remind them of what is happening and how they are doing.
  • Remind them of the time and date. Make sure they can see a clock or a calendar.
  • Listen to them and reassure them.
  • Make sure they have their glasses and hearing aid.
  • Help them to eat and drink.
  • Try to make sure that someone they know well is with them. This is often most important during the evening, when confusion often gets worse.
  • If they are in hospital, bring in some familiar objects from home.
  • Have a light on at night so that they can see where they are if they wake up.

How common is it?

  • About 2 in 10 hospital patients have a period of delirium.
  • Delirium is more common in people who:
    • are older
    • have memory problems

    • have poor hearing or eyesight

    • have recently had surgery

    • have a terminal illness

    • have an illness of the brain, such as an infection, a stroke or a head injury.

Why does it happen?

The most common causes of delirium are:

  • a urine or chest infection
  • having a high temperature
  • side-effects of medicine like pain killers and steroids
  • dehydration, low salt levels, low haemoglobin (anaemia)
  • liver or kidney problems 
  • suddenly stopping drugs or alcohol
  • major surgery
  • epilepsy
  • brain injury or infection
  • terminal illness
  • constipation
  • being in an unfamiliar place.

There is often more than one cause – and sometimes the cause is not found.

How long does it take to get better?

Delirium gets better when the cause is treated.  You can recover very quickly, but it can take several days or weeks.  People with dementia can take a particularly long time to get over delirium.

 How do you feel afterwards?

You may not remember what has happened, particularly if you had memory problems beforehand.  However, you may be left with unpleasant and frightening memories – and even worry that you are going mad.

It can be helpful to sit down with someone who can explain what happened.This might be a family member, a carer or your doctor. They can go through a diary of what happened each day. 

Most people feel relieved when they understand what happened and why.

Will it happen again?

You are more likely to have delirium again if you become medically unwell. Someone needs to keep an eye out for the warning signs that you are getting unwell again – whatever the original cause was. If they are worried they should get a doctor as soon as possible. If medical problems are treated early, this can prevent delirium from happening again.