Legal Series
Substitute Decision Making & Health Care

Substitute Decision Making & Health Care


A substitute decision maker is the person who makes decisions for a person that is found incapable.

Dementia and Alzheimer’s patients will all have to have one or more substitutes for their decisions eventually.

In Ontario, two key laws guide us on this issue. The Health Care Consent Act (“HCCA”) applies to health care decisions and the Substitute Decisions Act (“SDA”) applies to all other decisions. These two laws work together.

Who Decides a Substitute is Needed?

When a doctor proposes a treatment, the doctor must get the patient’s consent to go ahead with the treatment. Part of this process gives the doctor a chance to evaluate the patient’s ability to give consent. Only the doctor evaluates the patient’s capacity with respect to that treatment.

The doctor has to follow the test for capacity stated in the HCCA. The test determines the patient’s ability to understand the relevant information about the treatment, and the patient’s ability to appreciate the consequences of making a decision or not. If the doctor decides the patient is incapable, there is no option for a “second opinion” by calling in someone else. However, the patient can appeal the doctor’s finding of incapacity to the Consent and Capacity Board.

Who can be a Substitute?

Whenever a person is found incapable to make a treatment decision, the doctor must find a substitute decision maker. The law provides a list:

  1. Guardian of the person who has authority for treatment decisions
  2. Attorney named in power of attorney for personal care who has authority for treatment decisions
  3. A representative appointed by the Consent and Capacity Board
  4. Spouse or partner (does not have to be common law)
  5. Child or parent
  6. A parent with right of access only
  7. Brother or sister
  8. Any other relative

The doctor must seek a substitute in this order. If no one is found on this list, the Public Guardian and Trustee (PGT) becomes the substitute decision maker. If the patient or their family or friends do not want the PGT to make health decisions, either the patient or anyone else can apply to the Consent and Capacity Board to be appointed the person’s representative.

If more than one person is found in the same category and they all agree to act as substitutes, they must all agree on the decision otherwise the Public Guardian and Trustee will make the decision.

What if a Substitute does not want to be the Decision Maker?

The substitute must be “willing, able and available”:

  • “willing” means the substitute must agree to assume the responsibility
  • “able” means that:
    • the substitute has the mental capacity to make the treatment decision; if they do not, the doctor goes down the list to the next category
    • the substitute is 16 years or older
    • no court order or separation agreement prohibits the person’s access to the patient
  • “available” simply means that the substitute can be reached by any means of communication in a timely manner.

If a person is approached to become the substitute for health decisions and does not want to take on that responsibility, he or she can decline.

How does a Substitute make Decisions?

Substitutes should be informed of the principles upon which a decision should be made by the doctor or a lawyer.

Known Wishes

If the substitute knows the patient’s wishes regarding treatment, which were made when the patient had capacity, the substitute must honour those wishes. This would be the time to learn if the person has advance directives and assess whether they apply. But even if written advance directives exist, any wish made by the patient while capable – even orally – later than the written directive, prevails.

If the doctor decides the patient is incapable, there is no option for a “second opinion” by calling in someone else.

If the patient’s wishes would force the substitute to refuse the treatment, the substitute may apply to the Consent and Capacity Board to depart from those wishes. The doctor also may apply to the Board for permission for the substitute to depart from those wishes.

Best Interests

If the substitute does not know of a wish made while the patient was capable and that applies to the circumstances, or if it is impossible to comply with such a wish, the substitute must act in the person’s best interests.

The substitute must consider the patient’s values and beliefs and decide whether they would still act on those. The substitute also considers any wishes regarding the treatment that the patient made after losing capacity. Finally, the substitute requires information about the treatment from the doctor and must consider whether the treatment is likely to:

  • improve the patient’s condition;
  • prevent the patient from getting worse;
  • slow the rate at which the condition worsens;
  • whether the patient will improve, remain the same or get worse without treatment;
  • whether the benefits outweigh the risks of harm; and
  • whether any other treatment that is less intrusive would be as helpful.

If the doctor believes that the substitute is not acting in the patient’s best interests, he or she may challenge the decision before the Consent and Capacity Board.

Clearly, it is important to think about worsening health as soon as a diagnosis is received.

Clearly, it is important to think about worsening health as soon as a diagnosis is received. Every patient should carefully consider the list of substitutes for health care and whether they are happy with it or whether they would like to skip over someone in the hierarchy. Even if a dementia patient has lost the capacity to make a will, he or she could still have capacity to appoint an attorney with authority for health care. It would be best to consult with a lawyer as lawyers understand how to evaluate capacity in this context and will take careful notes in the event there are future challenges. Lastly, it is so important for people to discuss their wishes with their attorneys, family and friends so that those wishes may be honoured if possible.


PLEASE NOTE: The information provided in this article is for informational purposes only. It is general information and should not be taken to be a full and accurate discussion of the law on this topic, nor is it intended to be legal advice or to be relied upon as legal advice by the reader.

If you have questions about substitute decision making for health care decisions, you may contact the author:
Areta N. Lloyd

In Association With
Elder Law Group

About the author

Areta Lloyd

Read All Articles by Areta Read More Read Less

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