What delirium looks like
Some people become agitated and restless (hyperactive delirium). Others become quiet and withdrawn (hypoactive delirium), and some move between the two. The national delirium standard notes that the hypoactive form is more common in older people, is often missed and has a worse outlook 3.
Compared with people without delirium, people with delirium have a higher risk of death and of falls, longer hospital stays, and a greater chance of developing dementia 3. These findings come largely from hospital patients.
How common it is in residential care
A 2026 systematic review of nine studies of nursing home residents aged 65 or more estimated that about 19% had delirium at any one time. The studies varied widely, from 1% to 58%, and cognitive impairment was the factor most often linked with delirium 12.
In hospital, 10 to 18% of Australians aged 65 or over have delirium on admission, and a further 2 to 8% develop it during their stay 3.
Finding the cause
Delirium usually has a trigger, and often more than one. The national delirium standard names these among the common contributors 3.
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Acute illness. Infection of the chest, urine, skin or elsewhere, and other new illness 3.
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Medicines. A new or changed medicine, side effects, or several medicines together 3.
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Pain. Including pain the resident cannot describe 3.
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Constipation and urinary retention. Both are easy to miss without a deliberate check 3.
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Low oxygen, dehydration and abnormal sodium. Each can cause or worsen confusion 3.
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A urinary catheter. Listed in the standard as a risk factor in its own right 3.
Recognising it: the 4AT
The 4AT is a short test that takes less than two minutes. In a 2021 meta-analysis of 17 studies, it correctly identified about 88% of people with delirium and 88% of people without it 13. Most of those studies were in hospital wards and emergency departments; only one was in a care home 13. The national standard notes that it has been validated both for screening for cognitive impairment and for assessing delirium 3.
A test result is only as good as the baseline it is compared with. Family members and carers are often the best source of information about an acute change 3, and a note in the care plan describing the resident’s usual thinking, mobility and routine makes change easier to see.
Preventing delirium in residential care: the evidence
Graded on randomised evidence from long-term care. A 2019 Cochrane review found only three trials, and no trials of medicines for prevention 14.
Computer-triggered pharmacist medication review
Promising, not yet provenFewer new cases of delirium in one large US trial.
The evidence
A system that flagged medicines that may contribute to delirium and triggered a pharmacist review probably reduced new delirium (hazard ratio 0.42), with little or no effect on deaths, hospital admissions or falls. Moderate-certainty evidence from one trial 14.
In practice
It relied on information technology that many facilities may not have, as the reviewers noted 14.
A hydration-based program
Uncertain / conflictingToo small to say whether it prevents delirium.
The evidence
One trial of 98 residents; very low-certainty evidence 14.
Staff education on delirium risk factors
Uncertain / conflictingEffect on delirium could not be determined, although hospital admissions were probably lower.
The evidence
A small feasibility trial. The effect on delirium was uncertain, but admissions were probably reduced (risk ratio 0.67, moderate-certainty evidence) 14.
Care while the cause is treated
The measures the national standard lists for preventing delirium are also the basis of care once it has started: clear communication and reassurance, glasses and hearing aids, help with drinking and eating, attention to bladder and bowels, good pain relief, getting up and moving, a quiet environment, light that matches the time of day, and a clock and calendar 3.
The standard states that antipsychotic medicines are not recommended to treat delirium. It allows short-term use only when non-drug measures have not worked and there is an imminent risk of harm to the person or others 3.
Related pages on this site
- Diagnosis and assessment Dementia care section: telling delirium from dementia, and why cognitive testing during delirium misleads.
- Changed behaviours Dementia care section: new behaviour in dementia and the search for a cause.
- Anticholinergic burden Medicines section: medicines that add to confusion and delirium risk.
- Common symptoms and how they are managed in the facility Palliative care section: delirium and agitation near the end of life.
Sources cited on this page
- 3 Australian Commission on Safety and Quality in Health Care. Delirium Clinical Care Standard. Sydney: ACSQHC; first released 2016, revised September 2021. (Written mainly for hospitals; states it can be adapted for residential aged care.) View source
- 12 Houdelet-Oertel A, Lauer R, Molitor V, et al. Prevalence of delirium among older nursing home residents: a systematic review and meta-analysis. Eur Geriatr Med. 2026;17:1357–76. (Nine studies, 4,291 residents; high heterogeneity.) View source
- 13 Tieges Z, Maclullich AMJ, Anand A, et al. Diagnostic accuracy of the 4AT for delirium detection in older adults: systematic review and meta-analysis. Age Ageing. 2021;50:733–43. (17 studies, 3,702 observations; mostly hospital and emergency department settings, one care home.) View source
- 14 Woodhouse R, Burton JK, Rana N, Pang YL, Lister JE, Siddiqi N. Interventions for preventing delirium in older people in institutional long-term care. Cochrane Database Syst Rev. 2019;4:CD009537. (Three cluster randomised trials, 3,851 participants.) View source
See every source cited across the deteriorating resident section →
Written by Dr Josh Hatch, FRACGP. General information only, reflecting his reading of the published evidence as at November 2026. It is not individual medical advice, does not create a doctor–patient relationship, and must not be used to start, stop or change any treatment, and it does not set escalation rules for any facility. Antibiotic choices and doses follow current prescribing guidelines and local advice. Evidence, Australian regulatory requirements and local services change — always confirm current advice with the treating GP and the facility’s own procedures.
This is general education, not a clinical protocol. The doctors who practise with Umbrella Aged Care are independent general practitioners, and each makes their own clinical decisions with the resident and family. Your GP’s advice for an individual may differ from what is written here. If it does, please ask them to talk it through with you.