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Capacity assessments: Understanding the challenges for physicians

Doctor using a laptop to enter information, with male patient sitting opposite.

5 minutes

Published: December 2020

The information in this article was correct at the time of publishing

Physicians perform capacity assessments for different reasons and in different circumstances. They commonly assess capacity in their day-to-day practices for the purpose of obtaining informed consent to care. However, they may also be asked to conduct capacity assessments for reasons unrelated to clinical treatment.

Non-treatment capacity assessments require a physician’s medical judgment, but are not used for medical purposes. They may be needed to activate a power of attorney or representation agreement pursuant to laws such as Ontario’s Substitute Decisions Act or British Columbia’s Representation Agreement Act. They may also be requested by family members or lawyers if a patient changes a will or power of attorney. Physicians often wonder whether they are required to perform these non-treatment capacity assessments, or whether they need special training or certification to do so.

While treatment and non-treatment capacity assessments differ, they can both present unique challenges for physicians. Consider the following when assessing capacity for these two purposes.

I. Capacity assessments for treatment purposes

Capacity will vary with proposed treatment

Patients are generally capable of consenting to treatment if they are able to understand information relevant to making a decision, as well as the reasonably foreseeable consequences of making that decision.

However, capacity is always time and context specific. It should be re-evaluated any time a patient’s health changes and reconsidered with every new proposed treatment. Physicians cannot assume that a finding of capacity in relation to one treatment can carry over to a different treatment. Capacity must always be determined based on the facts and circumstances of each case.

New treatment prompts reassessment of capacity


A 75-year-old man with early-stage dementia presents at his family physician’s office accompanied by his wife. The physician diagnoses strep throat. In discussing the use of antibiotics, the physician determines that the patient understands the reasonably foreseeable consequences of using antibiotics. She therefore initiates this treatment.

Three weeks later, the same patient presents with severe anxiety. The physician believes that anti-anxiety medication would be helpful. However, she doesn’t believe that the patient understands the potentially serious side effects and risk of dependence associated with these drugs. Prior to prescribing the medication, the physician therefore seeks consent from the patient’s wife, who is his substitute decision-maker. The physician clearly documents the findings of her capacity assessment, as well as the consent provided by the substitute decision-maker.

Assessments may be used as evidence in legal proceedings

Physicians assessing a patient’s capacity to consent to treatment should be aware that such an assessment may later be used as evidence by third parties seeking to demonstrate that the patient did (or did not) have capacity for non-treatment purposes. A physician may be subpoenaed to provide evidence in court to this effect.

There are steps you can take to prepare for such an outcome, including preparing your documentation so that it clearly includes the basis of any finding, any tests performed to assess capacity, the dates and results of the assessments, and any second opinions sought.

Physician asked to comment on past capacity for non-treatment purpose


A family physician is contacted by an estates lawyer representing a patient’s son. The son is trying to challenge a change to his father’s will, which was made a year earlier. The lawyer asks the physician whether she saw the patient at that time. The physician says she did, but only assessed whether the patient was capable of consenting to medical treatment. Her notes clearly reflect the purpose and nature of the assessment she conducted.

Since the physician did not assess the patient for capacity unrelated to treatment in the previous year, she can tell the lawyer she does not feel sufficiently informed or comfortable commenting on the patient’s capacity to make financial or testamentary decisions at the relevant time. The physician can say with confidence only that she thought the patient had the capacity to make decisions about the medical care required.

II. Capacity assessments for non-treatment purposes

In most Canadian jurisdictions, the legal processes for appointing a guardian, appointing a personal representative, or activating a power of attorney or personal directive require an applicant to submit to either of the following:

  • a capacity assessment conducted by a physician
  • an affidavit from a physician attesting to the patient’s capacity

In some jurisdictions, physicians must meet certain requirements to become an assessor to conduct capacity assessments for the purpose of activating a power of attorney or appointing a power of attorney or guardian.2 Physicians who do not meet the statutory requirements should not conduct the assessment.

In jurisdictions where specific qualifications are not required, any physician may be approached to conduct a capacity assessment for the purpose of providing an opinion on the patient’s capacity. In these circumstances, physicians are usually asked only to assess a patient’s general capacity to understand information relevant to a decision and to appreciate the reasonably foreseeable consequences of a decision or failure to make a decision.

While there may be no legal obligation for physicians to conduct non-treatment capacity assessments, physicians should consider whether it is in their patient’s best interest to do so. Patients incapable of making important personal and financial decisions will require an appropriate substitute-decision maker be appointed, and this cannot happen without a physician’s assessment of, or opinion on, their capacity. It may also be difficult for some patients or families to retain a different, non-treating physician to conduct these assessments or provide these opinions.

Physicians who feel they do not have the experience or skill to form an opinion on a patient’s capacity for non-treatment purposes may choose to refer the patient to a specialized physician for further examination. Physicians who have the ability and experience to conduct non-treatment capacity assessments and refuse to do so may be subject to a medical regulatory authority (College) complaint.

Accurate documentation is critical

Accurate documentation is important regardless of the type of capacity assessment. In particular when assessing a patient’s capacity for non-treatment purposes, ensure your documentation clearly includes the purpose of the examination, the date of the examination, and the findings of the examination.

If you have questions about capacity assessments, contact the CMPA for advice.

The bottom line

  • Some physicians regularly conduct capacity assessments for treatment purposes. However, physicians may also be asked to conduct capacity assessments for reasons unrelated to treatment.
  • Physicians should re-consider a patient’s capacity to consent to treatment any time the patient’s health changes or a new treatment is proposed.
  • There may be circumstances where a physician needs to refer a patient to a more specialized physician or other healthcare professional to conduct a capacity assessment for either treatment or non-treatment purposes.


  1. This scenario is based on a compilation of CMPA case experience.
  2. For example, see Ontario’s Substitute Decisions Act, 1992 and Alberta’s Adult Guardianship and Trusteeship Act, 2008.

DISCLAIMER: The information contained in this learning material is for general educational purposes only and is not intended to provide specific professional medical or legal advice, nor to constitute a "standard of care" for Canadian healthcare professionals. The use of CMPA learning resources is subject to the foregoing as well as the CMPA's Terms of Use.