World Delirium Awareness Day (WDAD): Eight years of progress but…

13 March 2024

Dr Tomas Welsh is a Consultant Geriatrician based in Bath and an Honorary Senior Lecturer at the University of Bristol with a research interest in Alzheimer's disease and dementia. Dr Alexandra Thatcher is an ST4 Old Age Psychiatry Registrar.

Putting delirium on the map – World Delirium Awareness Day

World Delirium Awareness Day (WDAD) was established in 2016 by the International Federation of Delirium Societies (iDelirium) as a forum for patients, families and clinicians to raise awareness and share knowledge about latest developments in the field. 

WDAD – The Mission: To raise awareness and understanding of delirium. To promote early identification and management. To support and promote research. To improve the lives of individuals affected by delirium and their families.

Recognition and treatment of delirium has improved greatly over the years.  The first NICE Guideline¹ for delirium appeared in 2010, followed by SIGN Guidelines² in 2019.  These have been useful for unifying our approach towards delirium identification and treatment in the UK.  Multidisciplinary, international groups were established with the intention of sharing knowledge and training including the Network for Investigation of Delirium Uniting Scientists (NIDUS) in 2016 and this international working really came into its own during the pandemic when delirium was recognised as a common presenting feature of COVID-19 in older people.  World Delirium Day is an excellent opportunity for us to take stock and see how our understanding of delirium has progressed to date but also to do our bit to raise awareness and understanding of this condition outside of healthcare settings.

Delirium – where are we now?

Early identification

An ongoing priority of delirium clinicians and researchers has been to agree a consensus definition of delirium and its subtypes, as well as a standard approach to diagnosis.  NICE Guidance¹ on “Delirium: Prevention, diagnosis and management in hospital and long-term care” was updated in January 2023 to refine indicators of delirium which trigger assessment. The SIGN “Risk Reduction and management of delirium” was revalidated in 2022 and is due to be reviewed in 2025². The 4AT is now established as a simple, effective tool to identify delirium.

Research and education

NIDUS continues to be a collaborative multidisciplinary network spanning 27 institutions to advance research and training in delirium.  A review of their work published in February this year³ paints an impressive picture of their efforts so far including but not limited to; 1520 human and 225 animal studies in their research hub, 5600 articles organised and accessible via their website⁴, a white paper detailing a roadmap for advancement of delirium research⁵, more than 36 mentoring webinars provided by senior researchers and the implementation of a 3 day “Delirium Boot Camp” to train healthcare professionals.  So far, there have been 11 of these boot camps and 126 interprofessional, international mentees have attended. 

Improving care

Delirium can lead to distress for patients and carers as well as increased morbidity and mortality and longer hospital stays. It can impact on patients’ cognition later in life.  Understanding risk factors for delirium is important in  preventing delirium.  Treating delirium quickly results in more favourable outcomes, so the fast identification of possible delirium using neurophysiological, neuroimaging and blood and CSF biomarkers is being looked at. 

Another area of ongoing interest has been the link between delirium and dementia.  A recent meta-analysis of 23 studies and including 3562 patients with delirium and 6987 controls, showed a significant association between delirium and long-term cognitive decline⁷. The question that remains is what can be done to reduce the risk of dementia after an episode of delirium? The RecoverED Study (ongoing) may help unpick this.

WDAD 2024 – Humanising delirium care

It is easy to get carried away with the excitement of the newest scientific developments in investigating and treating delirium and to lose sight of the person experiencing delirium and how this can inform our understanding and treatment of delirium.  David Richards, an ARDS survivor, has documented and published his experience of delirium after spending 6 weeks in an ICU⁸.  It is an insightful and fascinating read into how the mind makes sense of what is being done to the body in a delirious state and should prompt questions on how we can improve our interactions with delirious patients.

WDAD24 - What can you do? (reproduced from

1) Raise awareness: Share information about delirium with friends, family, and colleagues.

2) Identify those at risk: Be aware of the risk factors for delirium. Identify individuals who may be at risk and take steps to prevent or manage delirium.

3) Know the signs: Understand the signs and symptoms of delirium, and be able to recognize them early.

4) Support research: Keep up-to-date and share the latest research on delirium.

5) Advocate: Advocate for better care for patients with delirium, including by pushing for more research and education, and policy changes.

6) Support and engage patients and families: Provide education to patients and families who are at risk of delirium and affected by delirium.

Thoughts for the future

There is still work to be done on unifying the definition of delirium and coming to a consensus on tools used internationally.  On the NIDUS website there are currently 45 different screening, diagnosis, and severity tools available to use. Multiple guidelines have been generated across the globe with significant variation. A World Delirium Consensus Guideline is overdue. Undergraduate and postgraduate education for healthcare workers must improve to deliver effective training on delirium.

NICE has made recommendations for delirium research to investigate diagnostic accuracy and ease of implementation of delirium assessment tools in people with pre-existing cognitive impairment, people who do not speak English as a first language, and patients in different settings, such as the emergency department or residential home. Research is also needed to assess if these tools are just as accurate just as accurate when used by different members of the multidisciplinary team’. ¹.

Internationally, there have been calls for increasing research into the pathophysiology of delirium as it is multifactorial and not well understood.  An improved understanding of the pathophysiological basis of delirium may lead to more targeted treatment for delirium and its subtypes.  In an ideal world, an international biomarker consortium with a standardised approach to specimen collection and recording could be developed for delirium research.  There is a precedent for such large-scale data banks including the UK Biobank, which to date has only been cited in three published papers on delirium since 2019 (⁹’¹⁰’¹¹).  An international delirium consortium would have the potential to accelerate current research efforts by providing a large data set of biological, electrophysiological and neuroimaging data. 


Huge progress has been made since WDAD was first conceived but there is still a great deal to be done to help raise awareness of cognitive health and to ensure that cognitively vulnerable people are supported to live well. Services that aim to promote brain health, and that facilitate rapid assessment, diagnosis and support to people developing delirium (avoiding hospitalisation) are still desperately needed. There is much to look forward to as better evidence and new interventions are developed and trialled, but the challenge ahead should not be underestimated.  


1.  NICE. Delirium: prevention, Diagnosis and Management in Hospital and long-term Care Clinical Guideline [Internet]. 2010. Available from:

2.  Risk reduction and management of delirium [Internet]. SIGN. Available from:

3.  Devlin JW, Jones RN, Inouye SK. Catalyzing delirium research: The NIDUS delirium network. Journal of the American Geriatrics Society. 2024 Feb 14;

4.  Clinicians - Delirium Central [Internet]. 2021 [cited 2024 Mar 12]. Available from:

5.  Oh ES, Akeju O, Avidan MS, et al. A roadmap to advance delirium research: Recommendations from the NIDUS Scientific Think Tank. Alzheimers Dement. 2020; 16(5): 726-733.

6.  Lucía Lozano-Vicario, García-Hermoso A, Bernardo Abel Cedeno-Veloz, Joaquín Fernández-Irigoyen, Santamaría E, Román Romero-Ortuno, et al. Biomarkers of delirium risk in older adults: a systematic review and meta-analysis. 2023 May 12;15.

7. Goldberg TE, Chen C, Wang Y, Jung E, Swanson A, Ing C, et al. Association of Delirium With Long-term Cognitive Decline: A Meta-analysis. JAMA Neurology. 2020 Nov 1;77(11):1373.

8.   Richards DB. Transitioning to reality: the diary of an ARDS survivor. Intensive Care Medicine. 2023 Oct 16;49(12):1571–5

9. Bowman K, Jones L, Pilling LC, Delgado J, Kuchel GA, Ferrucci L, et al. Vitamin D levels and risk of delirium. Neurology. 2019 Feb 15;92(12):e1387–94

10. Pilling LC, Jones LC, Masoli JAH, Delgado J, Atkins JL, Bowden J, et al. Low Vitamin D Levels and Risk of Incident Delirium in 351,000 Older UK Biobank Participants. Journal of the American Geriatrics Society. 2020 Oct 5;69(2):365–72.

11. Ulsa MC, Xi Z, Li P, Gaba A, Wong PM, Saxena R, et al. Association of Poor Sleep Burden in Middle Age and Older Adults With Risk for Delirium During Hospitalization. Fielding RA, editor. The Journals of Gerontology: Series A. 2021 Sep 24;77(3):507–16.



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