Can Doctors Override an Advance Directive in Ontario?

The Short Answer Is Complicated

Ontario physicians cannot administer treatment without consent. But they are also not obligated to provide treatment that they consider clinically inappropriate. These two rules create a tension that catches families off guard: your advance directive can stop a treatment you do not want, but it cannot force a treatment your doctor considers futile.

Understanding how this works under the Health Care Consent Act prevents the shock and conflict that regularly erupt at Ontario bedsides when families discover the limits of their planning.

How Consent Works in Ontario

Under the HCCA, every proposed treatment requires informed consent from a capable person. If the patient is capable, they consent or refuse directly. If the patient is incapable, consent must come from their substitute decision-maker — the attorney named in a Power of Attorney for Personal Care or the highest-ranking person in the statutory hierarchy.

A written advance directive, by itself, is not consent. Ontario classifies written healthcare instructions as "prior capable wishes." The SDM is legally required to consider these wishes when making decisions, but the consent itself comes from the SDM, not from the document.

This means a physician cannot simply ignore your written wishes. The SDM must follow them, and a physician who proceeds without the SDM's consent (or against the SDM's refusal) is violating the HCCA. If the physician believes the SDM is not properly following the patient's wishes, the physician can file a Form G application with the Consent and Capacity Board — but the physician cannot simply override the SDM and proceed.

When a Physician Can Refuse to Provide Treatment

The HCCA requires consent for treatment. It does not require physicians to offer treatments they consider clinically inappropriate. This is the area where families feel their wishes are being "overridden," even though the legal mechanics are different.

A patient cannot demand a specific treatment through an advance directive or through their SDM. If a physician determines that CPR would be medically futile — for example, in a patient with end-stage metastatic cancer and multi-organ failure — the physician is not obligated to offer CPR as a treatment option. The consent framework under the HCCA applies to proposed treatments. If the treatment is not proposed, there is nothing to consent to or refuse.

This does not mean the physician can unilaterally withdraw care. The physician must discuss goals of care with the SDM, explain why the proposed treatment plan does not include certain interventions, and document the clinical reasoning. If the SDM disagrees with the physician's assessment, the dispute can be escalated to the Consent and Capacity Board.

The "Level of Care" Form Confusion

Many Ontario hospitals use internal "Level of Care" or "Goals of Care" forms that ask families to indicate preferences about resuscitation, ventilation, and other interventions. These forms are not legally binding consent documents under the HCCA. Signing a facility's Level of Care form does not constitute advance consent to any treatment, and families are not legally required to sign one.

The confusion arises because hospital staff sometimes present these forms as though they carry the same weight as a formal consent process. They do not. The HCCA requires that consent be specific to each proposed treatment, informed by adequate information about the treatment's nature, risks, and alternatives, and given by a person who is capable or by their authorized SDM. A blanket Level of Care form does not meet this standard.

Families should understand that they can participate in Level of Care discussions without signing forms that they do not fully understand, and that the formal consent process under the HCCA operates separately from any facility-specific paperwork.

How to Protect Your Wishes

The strongest protection is a Power of Attorney for Personal Care with specific, detailed treatment instructions. Vague preferences like "no extraordinary measures" are easier for a clinical team to work around because they lack the specificity needed to apply to a concrete treatment decision. Instructions that address specific interventions in specific clinical contexts — CPR during a reversible event versus a terminal decline, ventilation as a bridge to recovery versus indefinite life support — are harder to dismiss.

The second layer of protection is the person you choose as your attorney. An attorney who understands your values, who has discussed specific scenarios with you, and who has the emotional resilience to advocate firmly at the bedside is the difference between wishes that shape decisions and wishes that get overruled by institutional momentum.

What a Physician Must Do

Even when a physician believes that a requested treatment is clinically inappropriate, they cannot simply stop providing care. The physician must continue providing the treatments that the SDM has consented to, must not provide treatments the SDM has refused, and must follow the dispute resolution mechanisms in the HCCA if there is a disagreement.

If the physician believes the SDM is not following the patient's prior capable wishes, the remedy is a Form G application to the CCB — not a unilateral override. If the SDM believes the physician is withholding a treatment that should be offered, the SDM can request a second opinion, ask for a transfer to another care team, or escalate through the hospital's patient advocacy process.

Our Ontario Advance Directive & Living Will Kit includes treatment preference worksheets designed to produce the specific, clinically grounded instructions that physicians take seriously — plus conversation scripts for discussing goals of care with the medical team and advocacy strategies for situations where your wishes are not being followed.

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