When you make your Will the last thing you want to happen is someone questioning your mental capacity. In layman’s term, you wouldn’t want your disinherited son, brother or relative to go in court after you die asking if you are sane or in the right mind when you made your will. What does this entail concerning your will and how can you prevent such things from happening?

Before we get to any advice and how to’s, let us first discuss what makes a person eligible for making a will that is considered legal.

  • Of legal age 21 years old up
  • Of sound mind (not insane or under the influence of others)

It’s pretty simple, right? Now, what constitutes to a will made with a sound mind? Let’s take a look at the principles established in the case Banks vs Goodfellow (1890) which became the framework for most mental capacity acts we have now.

  • You as a testator must understand that you are giving your property away
  • You must understand and recollect the extent of the property that you are giving away.
  • You must also understand the nature and extent of claims of the people you are including or excluding from your will.
  • You are not influenced by an insane delusion when you are disposing of these properties.

In a restatement of these principles by Muriel Chee, it is as follows:

  • You understand the nature of the act and what are the consequences of your actions
  • You know the extent of your property that you are disposing or giving away
  • You are aware who your beneficiaries are and can appreciate their claims to your property
  • You’re free from an abnormal state of mind (e.g. delusions) that might distort your feelings or judgment relevant to your will making.

Now, for someone to say that you lack the mental capacity two main determining factors or evidence are: factual component, these include proof seen by friends and relatives) as well as medical records. The court will check these evidences based on the Mental Capacity Act of Singapore. The act discusses the more thorough aspect that concludes if a person has the mental capacity or not. Undergoing a mental capacity assessment would be a good option as well if ever you’ve had a history of mental illness, then your best bet to prevent anyone from questioning your sanity is having legal medical proof. Do further reading on the Mental Capacity Act by clicking on this link https://sso.agc.gov.sg/Act/MCA2008   

Understanding the Burden of Proof

Let’s say someone decides to stake a claim at court that you made a will while not in a sane state of mind, what probable evidences can they present?

  • Medical proof
  • Witnesses

It is not the norm for a court to question a testator’s mental capacity, typically when a will appears to be rationally made, and it is duly executed, the testator is presumed to be in a sound mind. But, when a medical history of a mental disease or any kind of mental disability then a  will can be contested based on testamentary capacity.

So, how do you challenge a will based on the testator’s state of mind? You use a burden of proof. A burden of proof is basically the evidence you present in court to prove that a will is invalid. It can also be the evidence you present to defend the testator’s sanity. Its use depends on the side presenting the defence.

One way to refute any complaints about your will is taking a mental capacity assessment, doing this before making a Will gives your defence a solid evidence to use in court. Should in any way suffer a mental illness or disability, and recover from it having medical evidence is your best aid in proving that your Will is valid.


Your mental capacity is the main factor people look at when you give away your assets, are you aware of the risks or who will benefit and not benefit from your decision? Being able to grasp what is at stake is your best bet against people prodding you and your intentions.

If you want to learn more about Estate Planning then grab a copy of the book “The Rockwills Guide to Succession and Trusts in Wealth Management” it your comprehensive guide to understanding your wealth and how to manage it.