The preparation of wills for clients with mental health conditions presents unique challenges. Ensuring that a client possesses the necessary mental capacity to make a will (testamentary capacity) is critical for the will to be legally valid. This article outlines best practices for drafting wills for clients with mental health conditions, including how to assess capacity and manage potential challenges to will validity.
Assessing Testamentary Capacity with Fluctuating Mental Health
Testamentary capacity refers to the mental ability required to make a valid will. The standard is set out in the case of Banks v Goodfellow (1870) which requires that, at the time of making the will, the testator (the person making the will):
- Understands the nature and effect of making a will.
- Knows the extent of their property.
- Can comprehend and appreciate the claims to which they ought to give effect.
- Is not affected by any disorder of the mind that influences their decisions regarding distribution.
For clients with dementia, bipolar disorder, schizophrenia, or other disorders, capacity may fluctuate. A client may lack capacity at certain times but regain it during periods of lucidity. Practitioners must therefore assess capacity at the precise time instructions are taken and the will is executed, rather than making a generalised assessment.
Managing Challenges to Will Validity on Grounds of Capacity
Challenges to a will on the grounds of lack of testamentary capacity are increasingly common, particularly where there are sizeable estates or excluded beneficiaries. If a will is found to have been made when the testator lacked capacity, it will be declared invalid, and the estate distributed according to an earlier will or the intestacy rules.
To mitigate such risks, practitioners should consider the following:
Best Practices: Medical Evidence
Where a client has a mental health condition that may impact their testamentary capacity, it is best practice to follow the ‘Golden Rule’ of testamentary capacity and seek a medical opinion, ideally from a practitioner experienced in capacity assessment. This is particularly important where there is a history of mental health problems or where there is a risk of a future challenge to the will on the grounds of lack of capacity.
Medical evidence should be current and specific to the question of capacity at the relevant time. A formal capacity assessment might include:
- The client’s diagnosis (if any) and its effect on decision-making abilities.
- Assessment on the exact day of instructions/will execution.
- The professional’s opinion, with reference to the Banks v Goodfellow test.
Best Practices: Contemporaneous Notes
Practitioners should always keep comprehensive, contemporaneous notes of all interactions with the client. This is particularly relevant if the client has declined a medical assessment and the practitioner will be relying on their own capacity assessment. These notes should document:
- The client’s responses to questions relating to their estate, family, and intentions.
- Observations of the client’s coherence, awareness, and ability to weigh decisions.
- The steps taken to ascertain understanding (such as repeating questions or explanations in different forms).
Tips for Assessing Capacity
Where drafting wills for clients with mental health conditions, if you are completing your own testamentary capacity assessment, consider the following tips:
Use Simple Explanations and Language
Avoid using complex legal terminology where possible. Where this is unavoidable, ensure it is clearly explained to the client. Provide straightforward explanations of the effect of making a will. The client’s understanding should be checked by asking them to explain their decisions in their own words.
Ask Open and Probing Questions
Use questions that invite the client to demonstrate their understanding, such as:
- “Can you tell me who your family members are and what their relationship is to you?”
- “What property or assets do you own?”
- “Who would you like to leave your assets to, and why?”
Probe for the rationale behind choices, particularly where these deviate from expectations (for example, excluding a close family member).
Repeat and Summarise Key Points
Ask the client to repeat their intentions back in their own words. Restate key aspects of the will and confirm the client’s continued agreement. Assess whether the client’s answers are consistent throughout the meeting.
Consider Timing and Capacity Fluctuations
Try to meet the client at a time of day when they are at their best, according to their carers or family members. If capacity is variable, arrange multiple meetings or seek supplementary assessments as necessary.
Remain Alert to Red Flags
Watch for inconsistent instructions, memory lapses, inappropriate affect, or misunderstanding of family structure or assets.
Conclusion
In cases involving mental health conditions, the stakes are high. By following established legal standards, seeking medical input, and documenting thoroughly, practitioners can reduce the risk of future disputes and ensure that the client’s wishes are respected.
For further information on testamentary capacity, please consider joining our webinar on 4 November.
If you have subscribed to our Quiz Membership 2025, please find this article’s quiz here. You must be signed into the partner area of our website to access this.

