The question of mental capacity is an important consideration in will-making and can be a contentious issue. How often do we hear family members arguing over a loved-one’s ‘state-of-mind’ and ‘what Grandad would have wanted’ when sadly, his memory and ability to make reasonable decisions comes into question. This may be due simply to age, deteriorating health or a combination of both.

A person must have mental capacity to make or update a Will – this is one of the key elements to ensure the validity of a Will and limit the possibility of it being challenged on the grounds of testamentary capacity.

One way of reducing conflict and a potential challenge to a Will is to ensure a loved one (particularly if aged or in declining health) is encouraged to regularly review his or her Will and estate plan before mental capacity becomes an issue.

The test of mental capacity

The test of mental capacity was established almost 150 years ago in 1870, in a legal case Goods v Goodfellow. The language used reflects the era, but the key elements remain relevant:

It is essential to the exercise of such a power that a testator shall understand the nature of the act, and its effects; shall understand the extent of property of which he is disposing; shall be able to comprehend and appreciate the claims to which he ought to give effect; and with a view to the latter object, that no disorder of the mind shall poison his affections, pervert his sense of right, or prevent the exercise of his natural faculties – that no insane delusion shall influence his will in disposing of his property and bring about a disposal of it which, if the mind had been sound, would not have been made.

Translated to a more contemporary understanding, the Will-maker must:

  • understand the nature and effect of the Will;
  • understand the extent of the property in the Will;
  • understand the claims he / she ought to consider; and
  • be free of illogical beliefs that are not in sync with his / her level of education and surroundings.

What happens if a Will-maker lacks mental capacity?

Lawyers must ensure that a Will-maker’s interests are protected and have an obligation to question a Will-maker’s mental capacity if it is in doubt. The lawyer must be able to obtain instructions directly from the Will-maker and be satisfied that he or she understands the legal implications of the documents being prepared and signed.

Given the many possible perceptions of an ‘unsound mind’ or being free of ‘insane delusions’, this is not always an easy task. A testator, who is intermittently unsound, may still make a valid Will if it can be shown that the Will was made at a time of sanity.

Unfortunately, once the capacity of a Will-maker comes into question, additional steps are required to confirm his or her ability to properly understand the nature of the contemplated document.

At the least, this usually requires obtaining medical and / or psychiatric reports from practitioners which may add expense and cause additional stress and anxiety to the Will-maker and his or her family. The extra time required to obtain these reports and to establish mental capacity is itself an issue, particularly when a Will-maker’s health is declining.

If the Will-maker’s capacity cannot be established, then the Will cannot be made or an existing Will updated.

An outdated Will that clearly does not express the intentions of the deceased can be a major disappointment to the deceased’s family and loved ones.

If a Will is made or updated at a time when mental capacity is in dispute, a contentious challenge and / or a family provision claim may follow, after the testator dies.

What happens if no Will is made?

If no Will is made, then the Will-maker will die intestate and his or her assets will be distributed in accordance with pre-determined formulae set out in legislation in each state and territory.

Essentially, these rules provide for a specific order of distribution to the deceased person’s next of kin – those who receive an inheritance will depend on the individual and family circumstances of the deceased.

The distribution of an intestate estate generally reflects the moral expectations of society, but not always the wishes of the Will-maker. There are numerous reasons why a Will-maker may have wanted to leave out an expectant beneficiary or indeed include non-family members in the distribution of his or her estate. For a variety of reasons, the testator may also have wanted to allocate unequal shares to beneficiaries whom under the legislation would otherwise share equally.

Dying intestate therefore cannot guarantee that the Will-maker’s assets will be distributed as he or she intended.

Points to remember

The problems of intestacy or having an outdated Will can be avoided by ensuring a Will is made whilst a person is in good health and of sound mind. Some points to remember:

  • Mental incapacity can occur progressively or suddenly and can affect the old, the middle-aged and the young. Whilst we can all exercise caution and moderation, nobody is exempt from the fragility of life and an unpredictable future.
  • Determining mental capacity when in doubt is not straight-forward, will exacerbate the will-making procedure and add undue cost and stress to the process.
  • Planning your Will now and making the effort to review it regularly will safeguard your estate from the possibility of unintentional distributions.
  • Encourage your loved ones to review their Will and other estate planning documents when there is a change in personal or financial circumstances and particularly when they are ageing or in deteriorating health.
  • Lead by example and make or review your own Will and estate plan!


The real intentions of a testator cannot be established once he or she has died or is permanently incapacitated, unless a valid and up-to-date Will exists. Spending time on your estate planning today will avoid the uncertainty, additional costs and stress of trying to get it right when it is too late.

This article is intended to provide general information only. You should obtain professional advice before you undertake any course of action.

If you or someone you know wants more information or needs help or advice, please contact us on (02) 9818 2888 or email [email protected].