All About Estates

The Test for Capacity to Give Evidence and Special Accommodations

Section 16 of the Canada Evidence Act (“CEA”)[i] sets out the test for capacity to give evidence:

16(1) If a proposed witness is a person of fourteen years of age or older whose mental capacity is challenged, the court shall, before permitting the person to give evidence, conduct an inquiry to determine:

  • Whether the person understands the nature of an oath or a solemn affirmation; and
  • Whether the person is able to communicate the

Thus, only those who are not able to understand the nature of an oath or a solemn affirmation and/or those who are not able to communicate the evidence would be exempt from giving evidence.

Although there is an absence of medical literature assessing the capacity to give evidence, suggested criteria are available.[ii] When asked for a report on a client’s fitness to give evidence the authors suggested that the clinical evaluator consider:

  1. The person’s ability to give a clear, consistent accounting of any evidence.
  2. Whether the evidence given has any delusional quality, making it more probable that the evidence would be affected by mental illness.
  3. Whether the client appears to understand the role and nature of court proceedings and their obligations.
  4. The witness’ vulnerability to pressure of cross-examination and the possibility of the court proceedings affecting their mental health.

Note that the first and the third criteria follow the test for capacity to give evidence as per the CEA but the second and the fourth criteria do not.

The reliability of a witness’ testimony alluded to in the second criteria as being possibly impacted by delusions is not a prohibitive factor for giving evidence under the CEA.  It is the Court’s role to assess the probative value of testimony only and not that of an expert witness.

The fourth criterion described above alludes to a health advocate role of an expert witness that appears irrelevant to the legal test described in the CEA.  It regards a witness’ vulnerability to pressure of cross-examination and the possibility of the court proceedings affecting their mental health.

This health advocacy argument against giving evidence was tested in the case of Conseil québécois sur le tabac et la santé c. JTI-MacDonald Corp., 2012 QCCS 812 (CanLII)[iii] and is instructive for demonstrating the discrepancy between a clinical and legal opinion on capacity to give evidence.

In that case, the witness claimed that the stress of giving evidence would be detrimental to his mental health.  Justice Riordan wrote that the witness invoked a number of statutory provisions in support of his petition to not testify particularly the Code of Civil Procedure[iv] that provided the most concrete criteria to apply which was:

  1. All persons are competent to testify except those who, because of their physical or mental condition, are not in a fit state to report the facts of which they had knowledge, and any person competent to testify may be compelled to do so.

Justice Riordan wrote that the question therefore arises as to the proper application to be given to the expression “in a fit state”, given the particularities of the case and the warnings voiced by the medical reports.  As well, the Court must consider the issues of probability and degree of harm in balancing the interest of the witness against those of the administration of justice.

Justice Riordan stated that the Court is not insensitive to a physician’s protestations concerning “a prolonged deposition with intense questioning”.  Many witnesses require special accommodations and courts almost always find a modus operandi that provides for their physical and emotional comfort to the extent reasonable, while ensuring that the legal process goes forward as it must and the witness was compelled to testify.

Special accommodations can be made available in cases where testifying may provoke a high risk of affecting the health of a witness.  For example, the duration of uninterrupted testimony that a witness is asked to provide in any one day could be shortened.

In my clinical opinion, the means by which the Court could consider the extent of the potential adverse effect that testifying may impact the mental health of a witness should include the potential for exacerbation of previously documented mental illness.  The role of a medical-legal report of an expert witness could be to assist the Court in understanding the nature of a witness’ mental illness and to what degree their condition makes them vulnerable to any ill effects of providing testimony.

Just a few examples of many possibilities could include provocation of catastrophic reactions in those with dementia, precipitation of panic or depersonalization in those with of post-traumatic stress disorder, and exacerbation of psychosis in those with schizophrenia.  I suggest special accommodations should be particularly relevant when the stress of providing evidence could invoke suicidal ideation or need for repeat psychiatric hospitalization.

Nonetheless as I understand the CEA legal criteria, these special accommodations would not nullify capacity to give evidence as defined in the CEA.


[i] R.S.C. 1985, c. C-5

[ii] Jones, R., & Elliott, T. (2005), “Capacity to give evidence in court: issues that may arise when a client with dementia is a victim of crime”, Psychiatric Bulletin, 29(9), 324-326.



About Dr. Richard Shulman
Dr. Shulman is a geriatric psychiatrist at Trillium Health Partners and is an assistant professor at the University of Toronto. He is medical director of the Capacity Clinic and available for independent medical-legal capacity assessments.


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