What Is Impaired Decision-Making Capacity?
Impaired decision-making capacity means a person may not be able to make certain decisions for themselves, at a particular time, even with support. This may be temporary, fluctuating, or ongoing, and is often due to factors such as an acquired brain injury, intellectual disability, dementia, mental illness, or other health conditions that affect cognitive functioning.
In QCAT guardianship and administration applications, it must be clearly shown that a person’s capacity is impaired in relation to a specific type of decision—such as health care, financial management, or lifestyle matters.
Importantly, capacity is decision-specific. A person might be able to make some types of decisions, such as what they want to eat or where they’d like to live, but not others, such as complex legal or financial matters. It also depends on when the decision is being made and what support is provided at the time.
A person may have impaired capacity if they are unable to:
- Understand the nature and consequences of the decision,
- Retain and process relevant information for long enough to make a decision,
- Weigh the options and foresee possible outcomes, or
- Communicate their decision in a consistent way.
These difficulties must be significant and ongoing, not just occasional or due to stress, fatigue, or emotional distress in the moment.
It’s essential to understand that impaired capacity is not the same as:
- Making a choice that others disagree with,
- Choosing to take risks,
- Communicating in an unconventional way,
- Having limited literacy or English language skills,
- Needing support to understand information or express preferences.
Adults have the right to make decisions that others might think are unwise or risky. Risk alone is not evidence of impaired capacity. Everyone makes mistakes—and the dignity of risk is part of autonomy and personal growth.
Any consideration that a person may have impaired capacity should trigger a support-first approach. That means:
- Providing information in accessible formats,
- Giving the person time and space to process,
- Involving someone they trust to help understand the decision.
Only if these supports are tried and the person is still unable to make the decision should substitute decision-making (e.g. a QCAT application) be considered.
Additional Resources
Relevant Laws and Rights:
Guardianship and Administration Act 2000 (QLD) – outlines how capacity is defined and assessed, and presumes adults have capacity.
Human Rights Act 2019 (QLD) – protects the right to autonomy, privacy, and freedom.
UN Convention on the Rights of Persons with Disabilities (UNCRPD), Article 12 – recognises the equal right of people with disabilities to make decisions and receive the support they need to do so.
Guidelines for assessing decision-making capacity (Queensland Government Website) HERE
Queensland Capacity Assessment Guidelines (PDF from QLD Gov publications portal) HERE
Decision-making for Adults with impaired capacity (QCAT website) HERE