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Wills & Estates

How Is Mental Capacity Assessed Under Alberta's Adult Guardianship and Trusteeship Act?

TSL Written by the Treadstone Law Team· Updated November 13, 2026

This answer covers the law of Alberta.

In Alberta, capacity is assessed by checking whether the adult can understand the information relevant to a decision and appreciate its reasonably foreseeable consequences. The law presumes an adult has capacity until the contrary is determined. A disagreement with a decision does not by itself mean the person lacks capacity.

A formal assessment looks at whether the adult can make personal or financial decisions, including whether they understand the facts to consider and what could happen with each option. Before it, a doctor must give the adult a medical exam to rule out a temporary or reversible condition. Physicians and psychologists can do assessments for guardianship and trusteeship, and certain trained and approved health professionals, such as registered nurses, psychiatric nurses, social workers and occupational therapists, can be designated capacity assessors.

The assessor must complete a report in the prescribed form. A guardianship application must include that report, but if the adult refuses or is prevented from being assessed, the Court can decide on the available evidence. The assessment form is valid for 6 months for guardianship, trusteeship or co-decision-making applications. Fees are capped by regulation. A lawyer can confirm how this applies to your relative.

Key takeaways

  • Capacity means understanding the information relevant to a decision and appreciating its reasonably foreseeable consequences, and an adult is presumed to have it until the contrary is determined.
  • Disagreeing with a decision does not by itself mean a person lacks capacity.
  • Physicians and psychologists can do assessments, and certain trained and approved health professionals can be designated capacity assessors.
  • A doctor must first give the adult a medical exam to rule out a temporary or reversible condition, and the assessment form is valid for 6 months for these applications.
This is general information, not legal advice. It doesn’t create a lawyer–client relationship, and the rules can change. For advice on your situation, a Treadstone wills & estates lawyer can help.

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Sources

Links go to official government, court and regulator pages. The law changes — confirm you are reading the current version.

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