With rising rates of dementia in our community, we often hear clients worrying about whether being diagnosed means they (or someone they love) can no longer make a valid Will.
This worry is understandable. Fear of losing mental capacity and what that means for future planning is daunting and can be overwhelming. How can you know your wishes will be upheld, or if your Will will be questioned or challenged?
Thankfully, in Western Australia the answer is not black and white — having a dementia diagnosis does not automatically make your Will invalid. What matters is something more specific, and more human.
Let’s unpack it.
At a glance
- A dementia or Alzheimer’s diagnosis does not automatically invalidate a Will.
- The question is whether a person had “testamentary capacity” at the time the Will was made.
- The legal test for incapacity dates back to the 1870 case of Banks v Goodfellow. The test is made up of four key aspects.
- A person who has dementia can still make a valid Will during a “lucid interval”.
- The best way to protect against a Will challenge for a person with dementia is to have thorough medical and legal records made at the time.
Capacity, not diagnosis
Our law looks at the true capacity of a person, not the mere fact of their illness.
Someone living with dementia can still have the necessary capacity to make a legally valid Will. The reverse is also true — a person may be free of any diagnosis but can lack testamentary capacity for other reasons.
So, a diagnosis is a starting point for questions, but not a determining factor.
Instead of asking “did the person have dementia?”, the real inquiry should be “did they know and understand what they were doing when they made this Will?”
The test for testamentary capacity
To make a valid Will, a person must have testamentary capacity. This legal concept dates back to an 1870 English case, Banks v Goodfellow, and the test is still applied today by Australian courts.
A person has testamentary capacity if they:
- Understand what a Will is — the nature and effect of making a Will
- Understand what they own — the general extent of their property
- Know who might expect to benefit — the people with a claim on their estate, such as family
- Are free of any disorder of the mind that distorts their judgment or influences how they decide to leave their estate.
All four parts of the test matter. If a person shows signs that a delusion or serious cognitive impairment is interfering with their judgment at the time of making their Will, their capacity can be called into question.
The importance of timing, and lucid intervals
In Western Australia, testamentary capacity is assessed at the time a person signed their Will — not the week before or after, but then.
This is why “lucid intervals” are important for dementia sufferers. Symptoms can fluctuate, meaning a person may be confused and vague on some days but coherent and clear-headed on others. They might also be more aware and focused at certain times of the day than others.
In other words, if someone made their Will at a time when they genuinely understood what they were doing, it can be perfectly valid even if they had a dementia diagnosis or showed signs of memory loss and/or cognitive decline.
What matters is if, at the time of making the Will, they knew what they were doing and their understanding was unclouded.
This also applies to people with no diagnosis. If someone is struggling to grasp their situation or understand what they are doing when they sign a Will, it can be challenged for lack of capacity.
Who has to prove what?
Generally, a Will is presumed to be valid if it looks rational and was signed and witnessed correctly as required by law. This is called the “presumption of capacity”.
If someone wants to challenge the Will, they have to overturn this presumption by raising genuine doubts about the person’s capacity. If the challenger can do this, then it falls back on the person defending the Will to show there was sufficient capacity on the part of the Will maker. Here, evidence is everything — which is why it is so critical to have good records at the time the Will is made, to confirm the Will maker’s state of mind when they signed it.
Protecting a Will from a capacity challenge
For anyone in Western Australia who is thinking of making or redoing their Will later in life, these key steps can make a real difference:
- Ask a doctor to assess capacity as close as possible to the time the Will is made. Keep the doctor’s report in case it’s needed in future, and give a copy to the lawyer preparing the Will.
- Engage an experienced lawyer who will ask the right questions and take careful notes that can be relied on if needed in future.
- Act sooner, not later. Many people put off the process because it’s daunting or they haven’t made every decision, but if there is a diagnosis, early advice should be sought so a Will can be put in place before symptoms get worse. It is always better to plan while capacity is still clear, not once it’s in doubt: otherwise, there is a real risk of losing the chance to make a valid Will.
Following these simple steps can be the difference between a Will that is upheld and one that is tied up in dispute after you’re gone. Estate planning doesn’t have to be complicated, and getting the right advice early on is the best way to protect against future challenges.
The takeaway
In Western Australia, having dementia doesn’t automatically prevent a person from making a valid Will. The legal question is much more fair and precise: did the Will maker know and understand what they were doing at the time? A person with a diagnosis can absolutely still make a valid Will, if they have adequate capacity when they sign it – in line with the test in Banks v Goodfellow.
If you are concerned that someone you love has made a Will when they were not of sound mind capacity to make, or if you simply want to protect your own estate planning wishes — we are here to help you navigate your Will with clarity and care. Where there is genuine doubt about whether a Will is valid, our inheritance disputes team can advise on your options.
Speak with us today for clear, compassionate advice.
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