Mental Competency

  1. In a patient with a diagnosis that may increase the likelihood of cognitive and/or functional impairment (e.g., dementia, stroke, severe mental illness, head injury):
    • Assess the patient’s level of competence in the context of the decision(s) that the patient needs to make, recognizing that higher-risk decisions require higher cognitive capacity
    • Explain the purpose of the assessment and attempt to gain permission before you begin the assessment
    • Include other professionals when appropriate
  2. In an otherwise well patient with subtle changes in function (e.g., family concerns, medication errors, repetitive questions, decline in personal hygiene):
    • Perform an appropriate assessment of cognitive and functional abilities
    • Refer for further assessment when necessary
  3. When a patient is making high-stakes care decisions (e.g., surgery/no surgery, resuscitation status) think about the need to assess their decision-making ability.
  4. When capacity assessment is required, actively assess the patient’s ability to understand, appreciate, reason, and express a choice.
  5. When impaired decision-making ability is identified, attempt to establish severity, reversibility, and duration in order to plan treatment and regular reassessment.
  6. When a patient refuses to participate in capacity assessment:
    • Document their refusal
    • Continue to engage in the provision of safe care that is acceptable to the patient
    • Revisit the assessment when indicated
    • Pursue the need for a substitute decision maker when necessary

General Overview

  • Mental capacity implies a clinical status established by a healthcare professional
    • Capacity may change over time, and in the context of specific domains (medical, cognitive, functional)
  • Mental competency refers to a legal status judged by a legal professional
    • Situation-specific (care for self, sign out AMA, stand trial, sign a POA, change a will, financial decisions)
      • May be competent to make care decisions but not financial decisions
  • For consent to be considered valid:
    • Must be voluntary (without duress/coercion)
    • Patient must have the mental capacity to consent
      • Understands nature of proposed options, anticipated effect of options, and consequences of refusing
    • Patient must be properly informed
      • Diagnosis, proposed investigation/treatments, chance of success, alternatives, consequences of refusing


  • Standardized screening tests for cognitive decline (MMSE, MoCA)
  • Capacity and competence
    • Clinical interviewing
      • Understand information relevant to the decision
        • Cognitive ability to remember the information long enough to make the decision
          • Ask the patient to explain the nature of the condition/treatment/alternatives
      • Appreciate the reasonably foreseeable consequences of a decision or lack of decision
        • Weigh up information relevant to the decision
          • Possible outcomes of treatment, alternatives, lack of treatment
          • Realistic expectations
      • Communicate their decision – by talking, or any other means
    • Collateral information
    • Further assessment (eg. Occupational therapy - on-road assessment, kitchen-cooking assessment)
  • Advance Care directive (Living Will) prior to onset of impairment or early in progressive conditions
  • Substitute decision maker
    • If not assigned, by hierarchy:
      • Guardian appointed by the court
      • Power of Attorney for personal care
      • Representative appointed by Consent and Capacity Board
      • Spouse, common-law spouse or partner
      • Child (if >16yo) or parent (custodial)
      • Parent with right of access only (non-custodial parents)
      • Brother or sister
      • Any other relative
      • Office of the Public Guardian and Trustee