Understanding testamentary capacity

As a doctor, you may become involved in legal challenges involving a will. MPS medicolegal adviser Dr Alan Doris explains and advises on testamentary capacity

As the population ages, and the prevalence of mental disorders such as dementia increases, it is likely that doctors will more frequently be required to assess the mental capacity of their patients.

Mental capacity is the ability to make a decision. If a person lacks capacity, they have an impairment or disturbance that leaves them unable to make a decision. The loss of capacity may be partial or temporary and it is possible for a person to have capacity to make one specific decision but not another.

For a person to have capacity to make a particular decision they must understand the decision to be made and the information provided about the decision – the consequences of making a decision must be included in the information given.

The person must be able to retain the information given for long enough to make the decision; be able to weigh up the pros and cons of making the decision and to communicate their decision. It is important to note that the Code of Health and Disability Services Consumers’ Rights states at Right 7:

“(2) Every consumer must be presumed competent to make an informed choice and give informed consent, unless there are reasonable grounds for believing that the consumer is not competent”
“(3) Where a consumer has diminished competence, that consumer retains the right to make informed choices and give informed consent, to the extent appropriate to his or her level of competence.”

The provisions of the Protection of Personal and Property Rights Act 1988 (“PPPR Act”) protect the rights of people in situations where they are shown to lack capacity, either wholly or partially, to make decisions about their welfare or financial affairs.1

The PPPR Act also allows for people who have mental capacity to give an enduring power of attorney to another person, which comes into effect when capacity is lost. Where it is established that a person lacks mental capacity, the court can make a personal order regarding the person’s care or welfare, or can appoint another person as a property manager or welfare guardian to make decisions for the person.

Confirmation of such testamentary capacity may be sought at the time of making the will, and used as evidence of the validity of the will

The court may seek a medical opinion on the mental capacity of the person to assist in reaching a decision as to whether an order should be made.

Testamentary capacity

A specific situation where assessment of capacity is very important is when making a will. Confirmation of such testamentary capacity may be sought at the time of making the will, and used as evidence of the validity of the will should there be a legal challenge made after the person’s death.

Occasionally when the will of a deceased person is being contested, a doctor may be asked to give a retrospective opinion on testamentary capacity at the time the will was made, which can be very difficult.

Disputes over the distribution of the estate of a deceased person can be bitter and destructive of family relationships. A doctor can be drawn into this volatile situation if there are questions raised regarding the adequacy of the assessment of the deceased at the time of making a will. This is particularly likely when there are family members who feel they have been materially disadvantaged by a change to the will.

Where it can be established that the doctor has been negligent in performing an assessment of testamentary capacity at the time the will was created, and there has been a financial loss by someone as a result, he or she could be sued for damages.

It is essential that a doctor asked to give an opinion on the testamentary capacity of a patient follows a procedure which is robust, conforms to expert opinion and is able to withstand critical scrutiny.

The New Zealand case of Woodward v Smith2 involved a family member challenging the validity of changes made to the will of an elderly man after he had suffered a stroke. The Court of Appeal carefully described the test for testamentary capacity, and the correct process by which this should be carried out.

Testamentary capacity defined


Testamentary capacity is the specific ability to make a will. It is not necessary that someone is free from any mental difficulties or deterioration, and it is quite possible that someone may have testamentary capacity but not have capacity to do other things, such as manage their business affairs.

What is required to be established to certify that someone has testamentary capacity was set out in the English case of Banks v Goodfellow3 in 1870. The individual must understand the nature of the making of a will, its effects and the extent of their property and possessions. The person must also be able to appreciate the claims to the estate, which he ought to consider.

The person must also be “free of any disorder of the mind which would 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”.

It is not necessary that the person “should view his will with the eye of a lawyer, and comprehend its provisions in their legal form” but rather that they have a general understanding of the nature of a will, the extent of property, the state of their family, and those that may have a claim on their estate4.

Assessing testamentary capacity

The reporting judge in the Woodward case referred with approval to a paper published in the British Medical Journal, which recommended that doctors use the following process:5

  • Get a letter from the solicitor detailing the legal tests
  • Set aside enough time
  • Assess (according to standard medical knowledge) whether the patient has dementia
  • Check that the patient understands each of the Banks v Goodfellow criteria, being:
    (i) The nature and effect of making a will
    (ii) The extent of his or her estate
    (iii) The claims of those who might expect to benefit under the will
    (iv) The patient should not have a mental illness that influences making gifts in the will that would not otherwise have been made.
  • Record the patient’s answers verbatim
  • Check facts, such as the extent of the estate, with the solicitor
  • Ask about and review previous wills
  • Ask why potential beneficiaries are included or excluded
  • If in doubt as to capacity, seek a second opinion from an experienced professional.

While it is for the court to decide whether a will is valid or not, a careful medical assessment, fully documented, at the time the will was made can be very helpful to the court, or remove the need for legal proceedings completely. Such an evaluation will also stand the doctor in good stead should the assessment of mental capacity come under the critical spotlight in a dispute between possible beneficiaries.


  1. www.justice.govt.nz/courts/family-court/documents/pdf-pamphlets/Courts-044.pdf
  2. Woodward v Smith [2009] NZCA 215
  3. Banks v Goodfellow (1870) LR 5 QB 549
  4. Swinfen v Swinfen [1858] EngR 157
  5. Jacoby R and Steer P, How to assess capacity to make a will, BMJ 335:155 (2007)