Issues in Interdisciplinarity 2020-21/Evidence in the Euthanasia of Dementia Patients

Introduction.
The of patients is becoming increasingly contentious as the syndrome's prevalence rises with the ageing population, and concerns over healthcare costs and wellbeing grow. Euthanasia, the act of painlessly ending a life to relieve suffering, is, where legal, increasingly requested by dementia patients. Dementia is 'a group of related symptoms associated with a gradual decline in brain functioning'. 
Two branches of the debate especially generate interdisciplinary tensions. This chapter explores how tensions between , , and concerning this issue can be explained by the forms of evidence these disciplines examine. The first branch concerns judgements between an individual's life and the wellbeing of their society. The disciplines each bring valuable insights to the debate, yet struggle to reach a consensus on the right approach. The second concerns the rights of patients: examining differing disciplinary understandings of the syndrome, how they affect an individual's autonomy and approaches to valuing lives.
Individual and Collective Benefits.
The three disciplines have contrasting approaches to the conflict between benefits to individuals and their society. Ethics, the study of morality, forms arguments logically, based on axiomatic or subjective assumptions of the writer, discipline, and opposing positions. Anecdotal evidence is also used to highlight specific moral issues. Dresser, for example, criticises one case where a court prioritised 'economic and third party [family] concerns' over those of an 'incompetent' patient in permitting the cessation of life extending treatment. Logically extending from axioms of respect for autonomy and life, they view the decision as immoral, contrasting with sociological and medical positions. 
Sociology studies the behaviour and experience of individuals based on their demographics and groups, and is therefore concerned with the social influences on decision-making and the effects of decisions and policies on groups. Although many relevant studies are published in medical journals, their sociological approach constructively builds on medical and ethical discussions. 
Several studies explore the effects of euthanasia and dementia on the experiences of family members, suggesting that allowing euthanasia decreases levels of grief, trauma and depression in families. Roest's study found that, despite the legal, ethical and medical narratives suggesting otherwise, patients' families were central in both physician and patient decisions concerning euthanasia. Rather than criticising this, they suggest that the family's role should be further recognised, contradicting Dresser's conclusion. Thus, different conclusions result from different forms of evidence: ethical premises and anecdotes vs. qualitative, community-focused data.
Quality Adjusted Life Years (QALY) is a common measure used to distribute scarce resources and maximise usefulness of medical treatments. It calculates life expectancy, adjusted for any health conditions or disabilities a person lives with. The measurement therefore favours the young and healthy, leading to a reluctance to assign resources to patients that could remain in poor health after treatment. Due to its assumption of perfect health as an optimum, focus on maximising 'benefit' to society as a whole, and reliance on empirical rather than qualitative evidence or axiomatic values, the QALY is criticised in sociology and ethics for its discrimination against the ageing and disabled. This criticism is especially relevant to dementia patients, who face stigmas associated with dementia and financial pressures to fulfil their "special duty [to society] to die", decreasing their chances of receiving healthcare resources.
There are further ethical and sociological claims that dementia patients are depersonalised by the increasing medicalisation of old age, where they are perceived as unwell, as opposed to merely old.
Personhood.
The issue of personhood and dementia is highly intersectional, influenced from across the human sciences. Ethics, sociology and medicine have very different approaches to the concept's importance and how it should be preserved. 
The medical diagnosis of dementia includes cognitive, neuropsychological, and genetic tests. Research-wise, medicine focuses on physiological interventions and symptom-relieving drugs, generating the empirical evidence that medicine's physiological focus is grounded in. Due to this focus, the medical community faces considerable pressure for timely diagnosis, symptom relief, life-extending interventions, and rapid transitions into care programs.
Sociology explores the issue through a social constructionist framework and qualitative evidence, investigating the cultural, social and demographic factors that impact the prevalence and perception of the syndrome. This approach leads to a view of dementia that is based on its experience being an intersection of social position, symptoms, and the construction of dementia. Due to this evidence base and understanding of dementia as being socially constructed by medical classifications and media presentation, Johnstone and others argue that unnecessary stigma and fear have been generated around ageing by the medicalisation of dementia, leading to the depersonalisation of patients. This, and literature, showing how dementia prevalence and experience vary by demographics, has raised concerns that allowing euthanasia could become discriminatory.
This 'depersonalisation' is justified in medicine by the elements of competence to consent: communication of a choice, factual understanding, appreciation of consequences, and rationality. Thus, dementia patients are often not considered competent in their decisions, especially those who refuse food or treatment, or opt for euthanasia.
The concern about the euthanasia of dementia patients is shared by sections of sociological literature and medical practice, but for very different reasons. Tension arises from the sociological view that, in medicines neglect of patient autonomy, pessimism and 'pejorative interpretations of forgetfulness', they perpetuate a view of a 'black hole of ageing' which magnifies the patients desire for death while disrespecting requests or attempts to achieve it.
The consensus in ethics is generally that the wishes of the patient should be respected, and that advance directives are problematic in this regard. Dresser criticises the medical practice for neglecting the present patient when decisions are made based on their advance directives or another individuals assessment. Her argument is based on Parfit's 'Complex view' of personal identity, which is a view based on the subjective, qualitative observation that people feel disconnected from their previous selves and their values change over time. The evidential conflict with medicine is clear. As it concerns the physical changes in a body over time, viewing an individual as multiple persons over the course of their life seems incompatible with medical methods.
Conclusion.
There is little consensus between Medicine, Ethics and Sociology in regards to euthanasia and dementia. Each discipline draws from evidence that prioritises different areas of the issue of living with dementia. Medicine continues to do valuable work for those suffering from dementia, however, medical practice would benefit from sociological and ethical insights. Sociology is concerned with intersectional affects on the experience of dementia, criticising policies and representations that favour one group over another or create unnecessary suffering. It brings insights into how cultural and medical views can be improved to support people with dementia, as well as important social considerations in the euthanasia debate. Ethics, concerned with morality and individual rights, also raises valuable questions. It integrates these with sociological studies of how the treatment and rights of dementia patients could be improved in medical practice, especially concerning their right to die. There is encouraging research bridging this gap in medical sociology and medical ethics, however, significant difficulty exists in changing medical practice due to its highly practical focus.