Should we respect precedent autonomy in life-sustaining treatment decisions?

The recent judgement in the case of Re:M in which the Court held that it would be unlawful to withdraw artificial nutrition and hydration from a woman in a minimally conscious state raises a number of ethical issues of wide application. Central to these is the extent to which precedent autonomous decisions should be respected in the absence of a legally binding advance decision. Well-being interests can survive the loss of many of the psychological faculties that support personhood. A decision to respect precedent autonomy can contradict the well-being interests of the individual after capacity is lost. These decisions raise difficult questions about personal identity and about the threshold of evidence that is required of an earlier decision in order for it to be respected.