Doctors have a duty to ensure that patients in their care who refuse medical treatment are competent to do so. Doctors who comply with an incompetent patient’s refusal of treatment risk harm to the patient and are breaching their duty of care. On the other hand, doctors who treat a competent patient against the patient’s will violate his or her autonomy and commit a battery. The test of competence is a legal one, with the courts being the final arbiters in cases of doubt. Assessment of competence involves a three-step process of determining whether the patient (a) can comprehend and retain relevant information, (b) believes the information, and (c) can weigh the information in the balance and arrive at a choice. Asking patients a few simple questions can help doctors assess their competence.
Biegler P, Stewart C. Assessing competence to refuse medical treatment. Medical Journal of Australia 2001; 174: 522-525