Patients with decision-making capacity (DMC) have the right to refuse any treatment, even one that is life-sustaining. They also have the right to choose between treatment options, based on the principle of informed consent. Generally only when a patient lacks DMC does their Advance Directive or health care proxy have a role in medical decision-making. For these reasons it’s very important to determine whether a patient has DMC, which sometimes is a difficult determination to make, especially in cases of delirium or progressive dementia.
The first thing to note is that DMC is not the same as “competence,” although those terms are often used interchangeably. Competence is a legal term that is determined by a judge, and it is typically an all-or-nothing assessment. In other words, a patient is either competent or incompetent. (All adults are presumed to be competent unless declared otherwise by a judge.) Decision-making capacity, on the other hand, is a clinical determination made by a medical professional.
In addition, DMC is decision-dependent, meaning that a patient might have sufficient DMC to make a relatively straightforward decision, but not enough to make a complex medical decision. (This is important to recall when a patient who is showing some signs of confusion, because even if he can’t make medical decisions he may have enough DMC to name a proxy decision-maker.) In general, higher levels of DMC are required for decisions that are complex, have potentially grave consequences, or when a patient is making a decision contrary to what most people would opt for.
Finally, whereas in some states a patient without sufficient DMC does not have the right to refuse potentially beneficial treatment, Vermont is very protective of patient rights. Even if a patient lacks DMC, his refusal of treatment must be honored unless the proposed treatment is both emergent and critical, and his health care proxy (if he has named one) authorizes overriding their refusal.