'What would they want?’: Honouring decisions in dementia

Imagine that, at the age of 50, your friend tells you that if they go on to develop dementia and then another physical illness that could be fatal if untreated, they wouldn't want that treatment. Then imagine that it's 30 years in the future, and they are in that exact, awful situation. Due to the dementia — which, in this theoretical scenario, is still incurable — they've suffered a substantial loss of cognitive function. Only now, they're saying that they do want treatment for the physical disease. Which treatment preference would you feel compelled to honour?

James Toomey at Pace University and colleagues recruited 1445 US-based adults for a study that explored this difficult question. The participants read a series of vignettes in which the initial and later decisions about treatment varied — so that in some, the pre-dementia decision was 'no-treatment' but the post-dementia decision was 'treatment', while in others it was the other way around. The featured individual also varied, so that it involved the participant, their best friend, or a stranger. 

In all cases, the participants had to choose whether the first, pre-dementia treatment decision should be respected, or the later one, made after 'substantial, but not complete' cognitive decline. The vignette explained that this meant that the individual had lost many memories, generally did not recognise relatives, struggled to retain new information and didn't remember what they watched on TV or what was happening in the news.

"Much bioethical ink has been spilled over which preference should be respected in these cases," the researchers comment. The traditional bioethical, medical view, they add, is that when cognitive decline has been substantial, the pre-dementia decision should carry more weight. 

However, in this study of lay people's moral decision-making about others, the team found the opposite: most participants felt that the later preference should be respected. Only when they themselves were the focus of the vignette were they more likely to insist that the initial, pre-dementia treatment preference should be adhered to. 

Results from some other measures used in the study provide some insight into the reasons for this discrepancy. All participants indicated on a six-point scale the extent to which they believed the person in the vignette was still their 'true self'. This measure tapped into their judgements about the extent to which this person with substantial cognitive decline was still the same person, deep down. 

The team found clear links between scores on this scale and the participants' decisions. They felt that someone else — whether their best friend or a stranger – with the degree of cognitive decline described would still be closer to their true self than they would be. As the team writes, if the participant thought the person in the vignette was still their true self, despite their dementia, they were more likely to defer to their later treatment preference. 

Traditionally, a person's cognitive capacity has been considered to be important when it comes to medical decisions. These results suggest that lay people don't see things that way, instead feeling that the persistence — or otherwise — of the true self is more important. 

Because the results show that the participants made different judgements for themselves versus other people — including someone close to them — this raises potentially important practical questions. If asked to make a treatment decision about a family member in this position, "surrogate decision-makers might… underestimate the circumstances in which the person would have wanted their [initial] preference followed," the researchers write. The findings "challenge dominant assumptions in law, healthcare, and bioethics, and reveals an unexplored challenge for the practice of surrogate decision-making," they add. 

The team acknowledges some limitations to their research, such as the fact that it was conducted on a non-representative sample of Americans, which means the results may not generalise to even just the US as a whole. But the importance of the question of surrogate medical decision-making suggests that such studies should now be done.

Read the paper in full:

Toomey, J., Lewis, J., Hannikainen, I. R., & Earp, B. D. (2024). Advance Medical Decision-Making Differs Across First- and Third-Person Perspectives. AJOB Empirical Bioethics, 1–9. https://doi.org/10.1080/23294515.2024.2336900