A patient needs to give consent before undergoing any examination, investigation, procedure or treatment, except in limited circumstances.
A competent adult patient is someone who has the capacity to make treatment decisions for themselves. Capacity is present if the patient fulfils the following criteria:
- is able to comprehend and retain information
- can weigh that information in the balance to arrive at a choice.
A person without those abilities, due to, for example, dementia, intellectual disability, acquired brain injury or mental illness will have impaired capacity for medical decision making and will not be able to make medical treatment decisions themselves.1 Capacity is ‘decision specific’ and patients may have capacity to make some decisions but not others.
Where a person lacks capacity to make a particular decision, there are four ways in which decisions can be made by, or for, them:
- Before they lost capacity, the person may have made an advance care directive, which provides directions about medical treatment.
- A substitute decision maker can make the decision (based primarily on what they believe the person would have wanted).
- A tribunal or the Supreme Court can provide consent or make a treatment decision.
- In an emergency, healthcare decisions can be made by the treating team.
In circumstances in which an adult patient does not have the capacity to consent, there is specific guardianship legislation enacted in each Australian state and territory that provides for consent from a substitute decision maker (see Part C: Substitute decision makers).