Last updated 15 July 2022

Decision-making capacity is defined in Queensland in three parts within the Guardianship and Administration Act 2000 (Qld) (Guardianship Act):

  • understanding the nature and effect of the decision
  • deciding freely and voluntarily
  • communicating the decision in some way.

If a person is unable to satisfy all three parts, they are said to have impaired decision-making capacity. The impairment may be a result of a congenital intellectual disability, acquired brain injury, dementia, mental illness or some other cause. Determining capacity for decision-making is a legal and not a medical concept, but medical evidence may be informative.

The law recognises that a person’s decision-making capacity may be variable and fluctuating depending upon the type of decision to be made, the time the decision needs to be made, the adult’s physical health and the stresses they are experiencing. Capacity is not a black or white concept. It is graduated in accordance with the complexity of the specific decision required, the context in which the decision must be made, the timing of when the decision must be made and the support provided to make the decision.