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Informed consent

More than a signature

Other situations

Assault and battery

  • Touching (or treating) without consent is battery.
  • Battery includes treatment beyond or deviating significantly from that for which consent was given.

Case: A serious condition is discovered
Male physician consulting elderly female


Ms. Smith presents to a plastic surgeon for an augmentation mammoplasty. While operating, Dr. Adam finds a suspicious mass in the patient's left breast.

Frozen section biopsies confirm her impression of a malignancy. Dr. Adam performs a lumpectomy to save the patient from having an additional anaesthetic.


The patient is upset to discover she has had a lumpectomy without her consent even though the final pathology confirmed a malignancy.

Lesson learned

Dr. Adam was proceeding in the medical best interests of her patient and the lumpectomy was clearly medically indicated. However, the courts have repeatedly affirmed that good intentions of a physician cannot be substituted for the will of the patient.

Only when additional or alternative treatment is immediately necessary and vital to the health and life of the patient, not merely as a matter of convenience, should a physician proceed without express consent.

Patients with mental illness

Individuals with mental illnesses, including those admitted to a psychiatric facility, are capable of controlling and directing their medical care if they understand:
  • what is proposed and why
  • the risks and alternatives
  • the potential consequences of their decision

Patients who are "incapable" — Substitute decision makers

If your patient is not capable of consenting:
  • Follow the procedure for obtaining consent that is governed by legislation in your jurisdiction.
All jurisdictions have legislation (e.g. Mental Health Act or its equivalent), governing procedures for obtaining consent when a patient lacks capacity. Many jurisdictions also have legislation regarding advance directives for patients and the appointment of substitute decision makers
Substitute decision maker (SDM):  A person who is legally authorized to make decisions on behalf of the patient. This authority may be granted by the patient himself or herself with a legal document such as an advance medical directive, by legislation in each province/territory or by the courts.
 (SDM) for patients who may be unable to communicate their wishes.

An SDM can only give valid consent after receiving all the information that the patient would need before making a decision.

Sometimes it may be necessary to act when no SDM has been appointed. Physicians have often proceeded on the basis of the family's approval in such cases, but medical or legal consultation may be wise if:

  • There is disagreement among family members.
  • The proposed treatment carries significant risks.
  • There are questions or doubts about what is in the patient's "best interest."
  • There is dispute over whether or not a proposed treatment is "therapeutic."