Law & Medicine

Determining patients’ decisional capacity


Question: Mrs. Wong, age 80 years, has vascular dementia, and for the last 2 years has lived in a nursing home. She is forgetful and disoriented to time, person, and place, and totally dependent on others for all of her daily living needs. But she remains verbal and recognizes family members.

Recently, her glomerular filtration rate declined to less than 10% normal, and she has developed symptoms of uremia, i.e., nausea, vomiting, and intractable hiccups. The nephrologist has diagnosed end-stage renal failure and recommends hemodialysis, which will improve her renal symptoms and may extend her life by 1-2 years. But it will do nothing for her underlying dementia, which is progressive and irreversible.

Should she undergo hemodialysis? Choose the best single answer:

A. Mrs. Wong definitely lacks the capacity to decide whether to undergo hemodialysis.

B. A court-appointed guardian should make the decision.

C. Hemodialysis is futile and is medically contraindicated, inhumane, and unethical.

D. Hemodialysis is a life-extending form of comfort care, and therefore cannot be withheld.

E. The choice is hers if she understands the procedure and the consequences of her decision.

Answer: E. The terms competence and capacity are often used interchangeably in the health care context, although there are distinctions. Technically, a patient remains competent until a court says otherwise. On the other hand, the determination of medical decision-making capacity can be made by the attending physician and does not ordinarily require a court hearing.

Medical capacity can be determined by the use of the four-point test, which asks whether:

1. The patient understands the nature of the intervention.

2. The patient understands the consequences of the decision (especially refusal of treatment).

3. The patient is able to communicate his/her wishes.

4. Those wishes are compatible with the patient’s known values.

Dr. S.Y. Tan

Dr. S.Y. Tan

All patients are presumed to have capacity. A psychiatrist may assist in that determination, but this is usually unnecessary, and the treating physician makes the judgment. A decision that others consider “unwise, foolish, or ridiculous” does not necessarily mean there is a lack of capacity, and it can change over time, or be influenced by drugs, metabolic disturbances, and depression, among other things.

Courts tend to rule in favor of a finding of capacity. In one case, the court found no evidence that the patient’s “forgetfulness and confusion cause, or relate in any way to, impairment of her ability to understand that, in rejecting the amputation, she is, in effect, choosing death over life.”1

In another, the court opined, “However humble the background, sad and deprived the way of life, each individual should have the choice as to what is done to his body, if he is capable of understanding the consequences. This patient, although suffering from an organic brain disease, in the court’s opinion understands the consequences of his refusal. … I find that he has sufficient capacity and competence to consent to or refuse the proposed surgery.”2

Sometimes capacity is truly lacking. In a Tennessee case, Mary Northern, an elderly woman, refused amputation, denying that gangrene had caused her feet to be “dead, black, shriveled, rotting, and stinking.”3 Instead, she believed that they were merely blackened by soot or dust.

The court declared her incompetent, because she was “incapable of recognizing facts which would be obvious to a person of normal perception.” The court said that if she had acknowledged that her legs were gangrenous but refused amputation because she preferred death to the loss of her feet, she would have been considered competent to refuse surgery.

When the patient lacks capacity, a surrogate steps in. This may be a person previously designated by the patient as having durable power of attorney for health care decisions, and he/she is obligated to give voice to what the patient would have wanted. This is called substituted judgment.

Often, no surrogate has been formally mentioned, and a family member assumes the role; rarely, a court-appointed guardian takes over. When there is no knowledge of the patient’s wishes, the decision is then made in the patient’s best interests.

That a surrogate can make life and death decisions was first enunciated in the seminal case of Karen Ann Quinlan, where the New Jersey Supreme Court famously wrote, “The sad truth, however, is that she is grossly incompetent, and we cannot discern her supposed choice based on the testimony of her previous conversations with friends, where such testimony is without sufficient probative weight. Nevertheless, we have concluded that Karen’s right of privacy may be asserted on her behalf by her guardian under the peculiar circumstances here present.”4

The U.S. Supreme Court in Cruzan v. Director Missouri Department of Health has similarly held that an “incompetent person is not able to make an informed and voluntary choice to exercise a hypothetical right to refuse treatment or any other right. Such a ‘right’ must be exercised for her, if at all, by some sort of surrogate.”5 The court also opined that a state – in this case, Missouri – may apply a clear and convincing evidentiary standard in proceedings where a guardian seeks to discontinue nutrition and hydration.

Clear and convincing evidence is said to exist where there is a finding of high probability, based on evidence “so clear as to leave no substantial doubt” and “sufficiently strong to command the unhesitating assent of every reasonable mind.”

However, where a patient’s wishes are not clear and convincing, a court will be reluctant to order cessation of treatment, as in the landmark case of Wendland v. Wendland, where the California Supreme Court unanimously disallowed the discontinuation of a patient’s tube feedings.6

The patient, Robert Wendland, had regained consciousness after 14 months in a coma, but was left hemiparetic and incontinent, and could not feed by mouth or dress, bathe, and communicate consistently. He did not have an advance directive, but had made statements to the effect he would not want to live in a vegetative state.

His wife, Rose, refused to authorize reinsertion of his dislodged feeding tube, believing that Robert would not have wanted it replaced. The patient’s daughter and brother, as well as the hospital’s ethics committee, county ombudsman, and a court-appointed counsel, all agreed with the decision.

But the patient’s mother, Florence, went to court to block the action. The court determined that Robert’s statements were not clear and convincing, because they did not address his current condition, were not sufficiently specific, and were not necessarily intended to direct his medical care. Further, the patient’s spouse had failed to provide sufficient evidence that her decision was in her husband’s best interests.

Issues surrounding treatment at the end of life can be difficult and elusive. Even where there is an advance medical directive, statements made by patients in the document do not always comport with their eventual treatment decisions.

In a telling study, the authors found that only two-thirds of the time were decisions consistent.7 One-third of patients changed their preferences in the face of actual illness, usually in favor of treatments rejected in advance. Surrogate agreement was only 58%, and surrogates tended to overestimate their loved one’s desire for treatment.

The designation of who may be the legitimate alternative decision maker is another contentious issue, with laws varying widely from state to state.8

All of this may have in part prompted Singapore’s newly enacted Mental Capacity Act,9 which permits a surrogate to make wide-ranging decisions on behalf of an incapacitated person, to specifically exclude decisions regarding life-sustaining treatment and any measure that the physician “reasonably believes is necessary to prevent a serious deterioration” in the patient’s condition.

The decisional responsibility resides in the treating physician, who is obligated by law to make an effort to assist the patient to come to a decision, failing which it is made in the patient’s best interests.

Dr. Tan is emeritus professor of medicine and former adjunct professor of law at the University of Hawaii, Honolulu. This article is meant to be educational and does not constitute medical, ethical, or legal advice. For additional information, readers may contact the author at [email protected].


1. Lane v. Candura, 6 Mass. App. 377 (1978).

2. Matter of Roosevelt Hospital, N.Y.L.J. 13 Jan 1977 p. 7 (Sup. Ct., New York Co.).

3. State Dept Human Resources v. Northern, 563 SW 2d 197 (Tenn. Ct. App., 1978).

4. In the matter of Karen Quinlan, 355 A.2d 647 (N.J., 1976).

5. Cruzan v. Director Missouri Department of Health, 110 S. Ct. 2841 (1990).

6. Wendland v. Wendland, 28 P.3d 151 (Cal., 2001).

7. J Clin Ethics. 1998 Fall;9(3):258-62.

8. N Engl J Med. 2017 Apr 13;376(15):1478-82.

9. Singapore’s Mental Capacity Act (Chapter 177A).

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