Decision-making capacity

25 March 2024
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People make countless decisions every day. They can be deeply personal and are often informed by your values, your experiences and people closest to you. If you have the ability to make reasoned decisions for yourself about your personal, financial and legal matters, you are considered to have “legal capacity”. This is a complex legal concept that varies in different circumstances and can change over time. Adults are presumed to have full capacity unless shown otherwise.

It can be scary to think about losing capacity and being in a position where you are unable to make or communicate decisions for yourself. If you or a loved one have a neurological condition that causes cognitive decline, you may have already considered or experienced this possibility. However, it is something that can happen suddenly and unexpectedly to anyone, regardless of disability.

Although these discussions can be understandably difficult, talking about it can help prepare you for a future whereby a trusted individual can help make decisions for you.


While you have full capacity, you can appoint your preferred substitute decision-makers and prepare legal documents that record your preferences for personal, financial and legal matters. These documents are known as an Enduring Power of Guardianship (EPG) and an Enduring Power of Attorney (EPA). They specify the decisions your substitute decision-maker can make and the circumstances in which they can act.

The State Administrative Tribunal (SAT) also plays an important part in this process. Its role is to bring the EPA into effect where necessary by making a declaration that the donor does not have legal capacity. The SAT can also make orders revoking or varying the terms of an EPA, or recognising a power of attorney created in another jurisdiction as an EPA in WA. Once someone has lost their capacity to make decisions and can no longer create an EPA, the SAT can also hear an application for an administration order.

Figure 1. Summary of EPG and EPA key aspects

Who can make it/be appointed?Anyone 18+ with full legal capacityAnyone 18+ with full legal capacity
What types of decisions can the substitute decision-maker make?Personal, lifestyle, medical, and/or legal proceedingsFinancial and property matters
When does it come into effect?Only when you lose legal capacity – can be temporary or situation/decision-specificImmediately OR when SAT determines you have lost legal capacity
How is capacity determined?GP or medical specialist capacity assessment OR a SAT hearing (if uncertain)Only through a SAT hearing


An Advance Health Directive (AHD) is a legal document that records the treatment and care you consent to in specific circumstances. It will only be used by health professionals if you are seriously unwell or injured and are unable to make or communicate decisions about your care.

Your AHD sits at the top of what is known as the “hierarchy of treatment decision-makers”. If you lose capacity but don’t have an AHD, or a situation arises that isn’t covered by your AHD, health professionals will go down the hierarchy to find the first available adult who is willing to make the treatment decision. If your preferred substitute decision-maker is further down the hierarchy, you may want to consider making an EPG and appointing them as your enduring guardian to make them the next point of contact.

Figure 2. Hierarchy of Treatment Decision-Makers

Decision makers


We know this topic can feel rightfully overwhelming, but speaking with your trusted family, friends and/or health professionals can help you gather your thoughts on making an AHD, EPG or EPA to ensure you choose your decision-maker. Given their importance in communicating your life choices and preferences if you are ever unable to do so yourself, they require time and careful consideration to prepare.

Please see below for details on the free advisory services and resources (including step-by-step guides and the relevant forms) available for anyone ready to start the process or wanting more information.

Figure 3. Resources for making an AHD, EPG or EPA

Online ResourcesAdvisory Services
AHD WA Advance Care Planning Information Line | Ph: (08) 9222 2300 | Em:
EPG of the Public Advocate | Ph: 1300 858 455 | Em:
EPA of the Public Advocate | Ph: 1300 858 455 | Em: