Knowledge Exchange

Consent and Capacity: A Brief Overview of the Law in Ontario

Law and medicine intersect when a patient and health care team discuss treatment. Ontario’s law of consent to treatment applies to all types of treatment and requires procedures to protect the rights of incapable patients. Here is an overview of the important principles and legislation in the province.


The Health Care Consent Act, 1996, (the “HCCA”), says that for patient consent to be valid, the consent must be:
• related to the treatment
• informed
• given voluntarily, and
• not obtained through misrepresentation or fraud

Consent to a treatment is informed if:
• the person received the information that a reasonable person would require in order to make the decision, and
• the person received adequate responses to requests for additional information.

Meaningful consent requires material information, that is, it might reasonably make a difference to the choice being made. Information material to a treatment decision includes:
• The purpose, nature, and description of the procedure or intervention
• Reasonable available alternative treatment options
• The benefits of the proposed treatment and alternatives
• Material risks of the proposed treatment and alternatives
• Answers to any questions the patient might have

Consent is not, however, required in the case of an emergency. An “emergency” means the patient is apparently experiencing severe suffering or is at risk of serious bodily harm. This emergency exception does not apply, however, where:
• The capable patient or substitute decision maker is available and can be consulted with respect to the treatment, or
• The health care provider is aware of a valid advance directive that refuses consent for the particular treatment (see Malette v Shulman (1990), 72 OR (2d) 417 (ONCA)).


Capacity is the ability to make an informed choice with respect to a specific decision. A person is presumed to be capable with respect to treatment, and the presumption can only be displaced by evidence that a patient lacks the requisite elements of capacity, specifically:
• The ability to understand the information that is relevant to making a treatment decision, including the cognitive ability to process and retain the relevant information; and
• The ability to appreciate the reasonably foreseeable consequences of the decision or the lack of one, including the ability to apply the relevant information to his or her circumstances, and to be able to weigh the foreseeable risks and benefits of a decision or lack thereof.

The Supreme Court in Starson v Swayze, [2003] 1 SCR 722 emphasized that the HCCA requires a patient to have the ability to appreciate the consequences of a decision. It does not, however, require the actual appreciation of those consequences. The distinction is subtle but important.

Determining capacity should begin with asking about the patient’s actual appreciation of the parameters of the decision being made: the nature and purpose of the proposed treatment, alternative courses of action, foreseeable benefits and risks, and expected consequences of not having the treatment. If a patient shows an appreciation of these parameters, he has the ability to appreciate the decision he makes. If not, inquiry must be made into why the patient fails to appreciate consequences. A finding of incapacity is justified only if those reasons demonstrate that the patient’s mental disorder prevents him from having the ability to appreciate the foreseeable consequences of the decision.

A person found incapable must be advised of their legal rights except in an emergency. A health practitioner should follow the guidelines developed by her own professional body - in the case of physicians, the College’s Consent to Medical Treatment Policy ( If the person contests the finding of incapacity, she should apply to the Consent and Capacity Board. The physician’s role is to advise her how to proceed. A physician must not initiate any non-emergency treatment until the Consent and Capacity Board has rendered a decision, or 48 hours have passed and no formal application to the Board has been made.


If a person is found incapable, consent must be given by a substitute decision-maker, who is the highest individual on the following list who is available, willing, capable, and at least 16 years of age:
• A court appointed guardian for personal care
• An attorney for personal care
• A representative appointed by the Consent and Capacity Board
• The spouse, common law spouse, or partner
• Parents and children
• Brothers and sisters
• Any other relative by blood, marriage or adoption
• The Public Guardian and Trustee

If two or more persons with the same rank disagree, the Public Guardian and Trustee will decide. A substitute decision-maker decides about treatment based on the known wishes of the patient, while capable. These may be given verbally or in writing. If no relevant wishes are known, decisions must be based on the patient’s best interests, including his known values and beliefs, wishes made while incapable, and best interests.


Specific instructions about whether to accept or refuse treatment are binding on the substitute decision-maker, as relevant wishes expressed while capable. They may be included in a Power of Attorney for Personal Care or elsewhere. They are, however, instructions to the Attorney and not addressed to the health care team. It is the Attorney who must interpret them and come up with a decision.

A Power of Attorney for Personal Care must be made in writing with two witnesses. The capacity required to appoint an attorney is lower than the requirement to make treatment decisions, since it requires only:
• understanding whether the proposed attorney has a genuine concern for his welfare; and
• Appreciating that he may need to have the proposed attorney make decisions for him.

The lawyer preparing a Power of Attorney for Personal Care assesses capacity to make the document. Note that the Power of Attorney for personal care will also authorize the Attorney to make decisions about personal care other than treatment, such as nutrition, shelter, clothing, hygiene and safety.

Consent and capacity laws have a profound impact on individuals requiring treatment, and are designed to protect the autonomy of the affected individuals and prevent abuse and exploitation of vulnerable individuals.

Photo of Robert Gencarelli

Robert Gencarelli
Articling Student,
Cunningham, Swan, Caty, Little & Bonham LLP