Dementia and the Decision-Making Capacity Act

A case study provides an insight into the operation of new legislation on decision-making capacity

Dr Naushin Chowdhury, Third-Year Medical Student, School of Medicine, University of Limerick

July 13, 2023

Similar articles
  • A 75-year-old man presents to a GP practice with his son, who is also his carer. The patient was diagnosed with dementia four years previously, and his son now reports that his condition has been deteriorating in recent months. This is not the first time the patient’s son has attended the GP with concerns about the dementia. He reports that in the last year the patient has wandered away from his home without keys, has put himself in the path of oncoming traffic while walking his dog, and he frequently gets upset as he forgets where his personal items are kept at home. 

    Not only is there a concern for the patient’s safety, the patient’s son also feels that there is an increasing strain put on their relationship and on his capacity as a carer. When the GP asks the patient if he would be willing to consider moving into a nursing home or some other supported setting, the patient quickly dismisses the idea.     


    The Assisted Decision-Making (Capacity) Act, which was passed in 2015, amended in December of 2022, and finally commenced on April 26, 2023, centres around decision-making capacity, heavily emphasising the importance of patient autonomy.1 The Act underscores the importance of patient-centred decision-making. 

    The Assisted Decision-Making (Capacity) Act defines capacity as the “ability to understand, at the time that a decision has to be made, the nature and consequences of the decision to be made by him or her in the context of available choices at the time”.1 There are four basic criteria that need to be considered when understanding whether an individual has capacity: 

    • Understanding: can the patient comprehend the information provided? 

    • Retention: can the patient retain the information long enough to make a decision? 

    • Reasoning: can the patient use the information to weigh-up a decision by comparing various options open to them? 

    • Expression: can the patient adequately express and communicate their decision? 1

    By definition, assessment of capacity is a decision- and time-specific evaluation that can ultimately determine the outcome of a patient’s care. The Assisted Decision-Making (Capacity) Act addresses the need for a formula to determine capacity, especially in patients with dementia where cognitive fluctuations and a progressive illness may require a more dynamic approach to assessing decision-making capacity. It also includes a presumption that those whose capacity is in question, or may shortly be in question, in relation to a certain decision, have capacity. This applies irrespective of any pre-existing medical condition, including dementia.

    Cognitive fluctuations 

    Cognitive fluctuations are common in different forms of dementia, including Lewy body dementia and Alzheimer’s. Up to 12% of Alzheimer’s dementia patients can experience changes in episodic and semantic memory, disorganised thought, and concentration.2 ‘Sundowning’ is one phenomenon that occurs in Alzheimer’s patients and in other forms of dementia where cognitive fluctuations may occur specifically in the evening; patients may experience transient anxiety, confusion, agitation or disorientation.3 These fluctuations are strongly correlated with a decline in cognitive ability.4

    Although from a legal perspective they are distinct concepts, cognitive ability and capacity are intertwined. When cognition is impacted, such as in dementia, then it can significantly impair decision-making capacity.5 If a patient experiences temporary cognitive changes, it may be necessary to consider an alternative time for capacity assessment to optimise the patient’s opportunity to make decisions for themselves.  

    Patients with dementia may also engage with lifestyle modifications, rehabilitation programmes, or pharmacological interventions in order to try to improve their cognitive ability. Physical activity, nutrition, occupational therapy, and cognitive activities are some of the common recommendations that GPs make to patients with dementia in order to try and slow cognitive decline. 

    Pharmacological interventions such as acetylcholinesterase inhibitors and NMDA receptor antagonists have also been widely used to improve general cognitive functions in Alzheimer’s patients and other forms of dementia.6 Enhancements in cognitive ability may have significant implications in decision-making capacity in relation to decisions in the future. 

    Multidisciplinary consideration 

    Before beginning an assessment, it is necessary to have a clear understanding of the decision to be made, options available, and personal circumstances of the individual. A decision-making capacity assessment can sometimes be attempted in a brief consultation in a GP surgery. The responsibility of assessing a patient’s capacity, therefore, often falls on a single GP who may or may not have all the information necessary to make an assessment. 

    Patients with dementia may be linked in with several other health and social care professionals, such as public health nurses, occupational therapists, and social workers, and they may be in a position to provide relevant information and context, with the consent of the relevant patient. They may also provide insight into the will and preference of the individual should a decision be made that the individual lacks capacity and an intervention is necessary. 

    Consent to assessment

    The consent of the relevant individual must be obtained in advance of a capacity assessment and the individual must be informed of their right to refuse an assessment or stop an assessment at any time. 

    If the person is reluctant to participate, the assessor can take steps to reassure them and provide further information. However, if the relevant individual continues to refuse to consent and where an assessment is considered necessary, it may be necessary to seek a court order for a determination of the relevant person’s capacity as a last resort.

    Revisiting the case study

    The case presented earlier describes a man with dementia whose disease has significantly progressed in recent months. This has led to his son suggesting that he should now consider moving into a nursing home. However, the patient has continuously refused this option, prompting the investigation into his decision-making capacity. 

    The first thing for the GP in this case to consider is whether an assessment is appropriate. The GP must then seek the relevant party’s consent to assessment and information-sharing among the multidisciplinary team. This patient is linked with a social worker and an occupational therapist, among other healthcare providers, who may all provide valuable insights. 

    Multiple considerations need to be made when determining this patient’s capacity. To prevent implications of sundowning, a morning assessment should be considered as well as a multidisciplinary approach if the practitioner finds difficulty in determining capacity. Assessments under the Act are time-and decision-specific, recognising the possibility of cognitive fluctuations. 

    Irrespective of the outcome of the capacity assessment in this case, if the patient continues to protest against a change in his living circumstances, his will and preference remain central. While we await legislative guidance on deprivation of liberty safeguards, “healthcare professionals have a duty to ensure that involuntary admission to a nursing home of a dissenting person only occurs through a legal mechanism, irrespective of the inconvenience or expense to the healthcare system.”7


    As it stands, the current Act provides a time-specific framework for capacity assessments, and a requirement that assessments be carried out at the most suitable time for patients with fluctuating capacity. This will combat transient lapses in lack of cognition that may impact capacity, such as sundowning. 

    Modifications in patients’ lifestyles or addition of pharmacological interventions may improve cognitive function and impact capacity in the future. Moreover, adopting a multidisciplinary approach can provide a more comprehensive understanding of the decision to be made and the individual’s circumstances for the purpose of an assessment or their will and preferences if an intervention is deemed necessary. Ultimately, respecting a patient’s autonomy is the priority in medicine, and optimising decision-making capacity is crucial. 


    1. Assisted Decision-Making (Capacity) Act 2015.
    2. Escandon A., Al-Hammadi N, Galvin JE. Effect of cognitive fluctuation on neuropsychological performance in aging and dementia. Neurology 2010; 74(3): 210-217, available: doi: 10.1212/WNL.0b013e3181ca017d
    3. Canevelli M, Valletta M, Trebbastoni A, Sarli G, D’Antonio F, Tariciotti L, Lena CD, Bruno G. Sundowning in dementia: clinical relevance, pathophysiological determinants, and therapeutic approaches. Frontiers in Medicine 2016;3(73), available: doi: 10.3389/fmed.2016.00073 ​
    4. Trachsel M, Hermann H, Biller-Andorno N. Cognitive fluctuations as a challenge for the assessment of decision-making capacity in patients with dementia. American Journal of Alzheimer’s Disease & Other Dementias 2014;30(4): 360-363, available:
    5. Karlawish J.Assessment of decision-making capacity in adults. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on April 10, 2023.)
    6. Press D, Buss SS. Treatment of Alzheimer disease. In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on April 10, 2023)
    7. Donnelly M, Murray C. Ethical and legal debates in Irish healthcare: Confronting complexities. Manchester University Press; 2016
    © Medmedia Publications/Forum, Journal of the ICGP 2023