Decision-Making Capacity

Decision-making capacity is not a diagnosis, a cognitive score, or a permanent label. It is the ability to make one particular health-care decision at one particular time. A patient may be capable of consenting to routine medication administration yet unable to weigh the consequences of high-risk surgery. Capacity may return when delirium, hypoxia, intoxication, or medication effects resolve. Adults are presumed capable of consenting to or refusing treatment. The clinician must have a specific reason to question capacity and must be able to support a finding of incapacity; the patient does not have to prove competence. A diagnosis of dementia, psychosis, intellectual disability, or depression is a reason to assess the decision carefully, not a conclusion about the decision-maker. Canadian consent law is provincial and territorial. Ontario's Health Care Consent Act provides a useful statutory example: capacity has exactly two legal limbs. The patient must be able to: 1. understand the information relevant to the decision; and 2. appreciate the reasonably foreseeable consequences of making the decision or not making it. Clinicians often make those two limbs observable through a...