Writing a Will with Mental Illness UK (2026): Capacity, Depression & Diagnosis

Yes — having a mental health condition does not automatically mean you lack testamentary capacity. The legal test for capacity to make a will in England and Wales (the Banks v Goodfellow test from 1870) requires that at the time of signing the will you: (1) understand the nature of a will and its effects; (2) understand the extent of your estate in broad terms; (3) understand who might reasonably expect to benefit and be able to weigh their claims; and (4) are not suffering from a disorder of the mind that poisons your affections, perverts your sense of right, or prevents the exercise of your natural faculties in disposing of your estate. Mental health conditions that are well managed, in remission, or do not affect reasoning and judgement will not prevent a valid will. Millions of people with depression, anxiety disorders, bipolar disorder, and other conditions have made and continue to make legally valid wills.

Mild to moderate depression does not typically affect testamentary capacity. The Banks v Goodfellow test is concerned with whether a disorder of the mind distorts the testator's ability to understand and rationally evaluate their estate and the claims on it. Depression may affect motivation, concentration, and mood — but unless it is severe enough to cause delusional thinking, significant cognitive impairment, or a complete inability to weigh and understand information, it does not deprive a person of capacity. A person with depression who has a clear understanding of what they own, who they want to leave it to, and why, satisfies the test. If you are concerned about your capacity because of depression, speak to your GP or psychiatrist: a brief capacity assessment note can provide strong protection against any future challenge.

Bipolar disorder is an episodic condition — capacity may be fully present during stable periods and may be affected during severe manic or depressive episodes. A will made during a period of stability when the person has full insight, understands their assets and beneficiaries, and is not experiencing delusions or severe cognitive impairment is legally valid. Timing is important: aim to make or update the will during a period of stability, ideally when in contact with your mental health team. Document the circumstances of signing: a GP or psychiatrist capacity note made at or around the time of signing provides evidence that you had capacity on that specific occasion. This is particularly valuable because bipolar disorder is a condition that challengers might point to — pre-emptive documentation is the strongest defence.

Yes, if they have capacity at the time of signing. Schizophrenia affects individuals very differently. In periods of remission, when symptoms are controlled by medication and the person has good insight, there may be no impairment of testamentary capacity at all. However, if active psychosis, delusions, or severe cognitive disorganisation are present at the time of signing, there would be a real question about capacity — particularly the fourth limb of the Banks v Goodfellow test (whether a disorder of the mind perverts the sense of right or prevents rational evaluation of claims). For a person with schizophrenia, a formal capacity assessment by a psychiatrist at the time of will-making is strongly advisable — both to ensure the will is made correctly and to create contemporaneous evidence that protects the will from challenge.

Take these steps to protect the will from future challenge: (1) Time the signing: make or update your will during a period of stability, not during a crisis or acute episode. (2) Get a GP or psychiatrist capacity note: ask your doctor to write a brief note confirming that you have capacity to make a will on or close to the date of signing. The note should confirm you understand the nature of a will, the extent of your estate, and the claims of those who might benefit. (3) Use a solicitor to draft the will: a solicitor who meets you, takes your instructions, and witnesses the will creates a professional record of their assessment of your capacity. (4) Keep a brief note of your own: record why you are making the choices in the will — especially if you are excluding someone who might expect to benefit. (5) Store the will safely and tell your executor where it is. These steps are the 'golden rule' of will drafting in cases where capacity may be questioned.

Yes — a will can be challenged for lack of testamentary capacity, and a history of mental illness may be cited as evidence in support of a challenge. However, a diagnosis alone is not sufficient to set aside a will: the challenger must prove, on the balance of probabilities, that the testator lacked capacity at the specific moment of signing (not just that they had a condition that could affect capacity). If the will is properly witnessed, the testator gave coherent instructions, and there is contemporaneous evidence of capacity (a GP letter, a solicitor's file note), the challenge faces a high evidential hurdle. Courts are generally reluctant to overturn a carefully executed will — the bar for success is deliberate. Challenges based on mental illness are more likely to succeed when: the will was made during a known severe episode; the testator had recently been sectioned or hospitalised; or there is no contemporaneous capacity evidence and the will contains surprising or irrational provisions.

An LPA attorney cannot change the donor's will — that is expressly outside the attorney's powers. If a person has already lost testamentary capacity, the only route to making a statutory will on their behalf is an application to the Court of Protection under section 18 of the Mental Capacity Act 2005. The Court of Protection can authorise a statutory will reflecting what the person would have chosen if they had capacity — taking into account their known values, relationships, and previously expressed wishes. The process requires a formal capacity assessment, a court application (forms COP1 and supporting evidence), and a court hearing. It is used relatively rarely — for cases where a significant estate would otherwise pass under intestacy in a way that does not reflect the person's wishes. The cost is significant (£1,000–£3,000+ in fees) and the process takes many months.