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This guideline covers diagnosing and treating delirium in people aged 18 and over in hospital and in long-term residential care or a nursing home. It also covers identifying people at risk of developing delirium in these settings and preventing onset. It aims to improve diagnosis of delirium and reduce hospital stays and complications

In March 2019 NICE removed the use of olanzapine for the treatment of delirium in people who are distressed or considered a risk to themselves or others

NICE has published separate advice for the care of people with alcohol-related physical health problems, including delirium related to alcohol use (known as delirium tremens)

Please note that this Guidelines summary covers the key points for primary care. Please refer to the full guideline for the complete set of recommendations.


  • Delirium (sometimes called ‘acute confusional state’) is a common clinical syndrome characterised by disturbed consciousness, cognitive function or perception, which has an acute onset and fluctuating course. It usually develops over 1–2 days. It is a serious condition that is associated with poor outcomes. However, it can be prevented and treated if dealt with urgently
  • Delirium can be hypoactive or hyperactive but some people show signs of both (mixed). People with hyperactive delirium have heightened arousal and can be restless, agitated and aggressive. People with hypoactive delirium become withdrawn, quiet and sleepy. Hypoactive and mixed delirium can be more difficult to recognise
  • It can be difficult to distinguish between delirium and dementia and some people may have both conditions. If clinical uncertainty exists over the diagnosis, the person should be managed initially for delirium

Risk factor assessment

  • When people first present to hospital or long-term care, assess them for the following risk factors. If any of these risk factors is present, the person is at risk of delirium:
    • Age 65 years or older
    • Cognitive impairment (past or present) and/or dementia. If cognitive impairment is suspected, confirm it using a standardised and validated cognitive impairment measure
    • Current hip fracture
    • Severe illness (a clinical condition that is deteriorating or is at risk of deterioration)
  • Observe people at every opportunity for any changes in the risk factors for delirium

Indicators of delirium: at presentation

  • At presentation, assess people at risk for recent (within hours or days) changes or fluctuations in behaviour. These may be reported by the person at risk, or a carer or relative. Be particularly vigilant for behaviour indicating hypoactive delirium (marked*). These behaviour changes may affect:
    • Cognitive function: for example, worsened concentration*, slow responses*, confusion
    • Perception: for example, visual or auditory hallucinations
    • Physical function: for example, reduced mobility*, reduced movement*, restlessness, agitation, changes in appetite*, sleep disturbance
    • Social behaviour: for example, lack of cooperation with reasonable requests, withdrawal*, or alterations in communication, mood and/or attitude
  • If any of these behaviour changes are present, a healthcare professional who is trained and competent in diagnosing delirium should carry out a clinical assessment to confirm the diagnosis

Interventions to prevent delirium

  • Ensure that people at risk of delirium are cared for by a team of healthcare professionals who are familiar to the person at risk. Avoid moving people within and between wards or rooms unless absolutely necessary
  • Give a tailored multicomponent intervention package:
    • Within 24 hours of admission, assess people at risk for clinical factors contributing to delirium
    • Based on the results of this assessment, provide a multicomponent intervention tailored to the person’s individual needs and care setting
  • The tailored multicomponent intervention package should be delivered by a multidisciplinary team trained and competent in delirium prevention
  • Address cognitive impairment and/or disorientation by:
    • providing appropriate lighting and clear signage; a clock (consider providing a 24-hour clock in critical care) and a calendar should also be easily visible to the person at risk
    • talking to the person to reorientate them by explaining where they are, who they are, and what your role is
    • introducing cognitively stimulating activities (for example, reminiscence)
    • facilitating regular visits from family and friends
  • Address dehydration and/or constipation by:
    • ensuring adequate fluid intake to prevent dehydration by encouraging the person to drink—consider offering subcutaneous or intravenous fluids if necessary
    • taking advice if necessary when managing fluid balance in people with comorbidities (for example, heart failure or chronic kidney disease)
  • Assess for hypoxia and optimise oxygen saturation if necessary, as clinically appropriate
  • Address infection by:
    • looking for and treating infection
    • avoiding unnecessary catheterisation
    • implementing infection control procedures in line with the NICE guideline on healthcare-associated infections
  • Address immobility or limited mobility through the following actions:
    • Encourage people to:
      • mobilise soon after surgery
      • walk (provide appropriate walking aids if needed—these should be accessible at all times)
  • Encourage all people, including those unable to walk, to carry out active range-of-motion exercises.
  • Address pain by:
    • assessing for pain
    • looking for non-verbal signs of pain, particularly in those with communication difficulties (for example, people with learning difficulties or dementia, or people on a ventilator or who have a tracheostomy)
    • starting and reviewing appropriate pain management in any person in whom pain is identified or suspected
  • Carry out a medication review for people taking multiple drugs, taking into account both the type and number of medications. For information on medicines optimisation see the NICE guideline on medicines optimisation
  • Address poor nutrition by:
    • following the advice given on nutrition in the NICE guideline on nutrition support for adults
    • if people have dentures, ensuring they fit properly
  • Address sensory impairment by:
    • resolving any reversible cause of the impairment, such as impacted ear wax
    • ensuring hearing and visual aids are available to and used by people who need them, and that they are in good working order
  • Promote good sleep patterns and sleep hygiene by:
    • avoiding nursing or medical procedures during sleeping hours, if possible
    • scheduling medication rounds to avoid disturbing sleep
    • reducing noise to a minimum during sleep periods

Indicators of delirium: daily observations

  • Observe, at least daily, all people in hospital or long-term care for recent (within hours or days) changes or fluctuations in usual behaviour. These may be reported by the person at risk, or a carer or relative. If any of these behaviour changes is present, a healthcare professional who is trained and competent in the diagnosis of delirium should carry out a clinical assessment to confirm the diagnosis

Diagnosis (specialist clinical assessment)

  • If indicators of delirium are identified, carry out a clinical assessment based on the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criteria or short Confusion Assessment Method (short CAM) to confirm the diagnosis. In critical care or in the recovery room after surgery, CAM‑ICU should be used. A healthcare professional who is trained and competent in the diagnosis of delirium should carry out the assessment. If there is difficulty distinguishing between the diagnoses of delirium, dementia or delirium superimposed on dementia, treat for delirium first
  • Ensure that the diagnosis of delirium is documented both in the person’s hospital record and in their primary care health record

Treating delirium

Initial management

  • In people diagnosed with delirium, identify and manage the possible underlying cause or combination of causes
  • Ensure effective communication and reorientation (for example explaining where the person is, who they are, and what your role is) and provide reassurance for people diagnosed with delirium. Consider involving family, friends and carers to help with this. Provide a suitable care environment

Distressed people

  • If a person with delirium is distressed or considered a risk to themselves or others, first use verbal and non-verbal techniques to de-escalate the situation. For more information on de-escalation techniques, see the NICE guideline on violence and aggression. Distress may be less evident in people with hypoactive delirium, who can still become distressed by, for example, psychotic symptoms
  • If a person with delirium is distressed or considered a risk to themselves or others and verbal and non-verbal de-escalation techniques are ineffective or inappropriate, consider giving short-term (usually for 1 week or less) haloperidol. Start at the lowest clinically appropriate dose and titrate cautiously according to symptoms
  • Use antipsychotic drugs with caution or not at all for people with conditions such as Parkinson’s disease or dementia with Lewy bodies§

If delirium does not resolve

  • For people in whom delirium does not resolve:
    • Re-evaluate for underlying causes
    • Follow up and assess for possible dementia

1.7 Information and support

  • Offer information to people who are at risk of delirium or who have delirium, and their family and/or carers, which:
    • informs them that delirium is common and usually temporary
    • describes people’s experience of delirium
    • encourages people at risk and their families and/or carers to tell their healthcare team about any sudden changes or fluctuations in behaviour
    • encourages the person who has had delirium to share their experience of delirium with the healthcare professional during recovery
    • advises the person of any support groups
  • Ensure that information provided meets the cultural, cognitive and language needs of the person


† For guidance on diagnosing dementia, see diagnosis in the NICE guideline on dementia
‡ For further information on recognising and responding to acute illness in adults in hospital, see the NICE guideline on acutely ill adults in hospital
§ For more information on the use of antipsychotics for these conditions, see the NICE guidelines on Parkinson’s disease and dementia
¶ For guidance on dementia, see the NICE guideline on dementia


© NICE 2019. Delirium: prevention, diagnosis and management. Available from: www.nice.org.uk/CG103. All rights reserved. Subject to Notice of rights

NICE guidance is prepared for the National Health Service in England. All NICE guidance is subject to regular review and may be updated or withdrawn. NICE accepts no responsibility for the use of its content in this product/publication 

Published date: .

Last updated: 14