Can Someone With Dementia Sign a Will, Trust, or Contract in New York?

Short answer: Yes, a person with dementia can sometimes sign valid legal documents in New York — but it depends on which document is being signed and the person's mental state at the moment of signing. New York law applies different capacity standards to wills, trusts, and contracts. A diagnosis of dementia, by itself, does not automatically invalidate a signature. What matters is whether the signer understood the specific transaction at the relevant time.

This guide explains the three distinct capacity standards under New York law, how a will signed by someone with dementia is challenged in Surrogate's Court, and the practical safeguards that can protect a document from later attack.

Three Different Capacity Standards Under New York Law

One of the most common and costly mistakes people make is assuming that "mental capacity" means the same thing for every legal document. It does not. Under New York law, the bar a person must clear depends on the type of document. From lowest to highest:

• Testamentary capacity (for a will) — the lowest standard.
• Capacity to create or amend a trust — generally aligned with testamentary capacity when the trust is testamentary in nature, but closer to contractual capacity for trusts that operate like commercial agreements.
• Contractual capacity — the highest standard.

Because these standards differ, a person with mild or moderate dementia might have valid capacity to make a will while lacking the capacity to sell their home or sign a complex financial contract.

1. Testamentary Capacity — The Lowest Bar (Wills)

To make a valid will in New York, the testator must be at least 18 years old and "of sound mind and memory" under EPTL 3-1.1. New York's leading case on the subject, Matter of Kumstar, 66 N.Y.2d 691 (1985), sets out the three-part test. At the time of signing, the testator must have understood:

1. The nature and consequences of executing a will — that they were signing a document that disposes of their property at death;
2. The nature and extent of their property — in general terms, what they own; and
3. The natural objects of their bounty — who their family members and natural beneficiaries are (children, spouse, etc.).

Notably, this is a low threshold. New York courts have repeatedly held that a person can have testamentary capacity even while suffering from a serious illness, old age, failing memory, or a degree of dementia. A testator need not have the capacity to manage all of their affairs to make a valid will. The relevant question is the testator's understanding at the moment of execution, not their general mental health.

2. Capacity to Create a Trust

The capacity required to create a trust depends on the nature of the trust. A testamentary trust (one created within a will) is held to the testamentary-capacity standard. A revocable living trust used as a will substitute is generally evaluated under a standard close to testamentary capacity. However, an irrevocable trust that resembles a binding commercial arrangement — transferring assets in a way the grantor cannot undo — can be measured against the higher contractual standard. Because trusts vary widely, the applicable standard is fact-specific.

3. Contractual Capacity — The Highest Bar

To enter a binding contract in New York, a person must be able to understand the nature and consequences of the specific transaction and the rights and obligations it creates. A contract signed by someone who lacked the mental capacity to understand it is generally voidable. This is a more demanding standard than testamentary capacity because contracts often involve ongoing, reciprocal obligations — understanding terms, payment, performance, and consequences of breach — rather than the simpler act of directing who inherits property after death.

For context, the basic age requirement to contract in New York is 18, although minors may contract in limited situations such as for necessaries or with appropriate consent. The far more common dispute, however, is over mental capacity, not age.

Dementia Does Not Equal Incapacity

Dementia is a progressive condition with a wide spectrum of severity, and its effect on legal capacity is never automatic. A person in the early or even middle stages of dementia may fully understand a simple will on a given day. Conversely, a person with advanced dementia who can no longer recognize family members or communicate is unlikely to meet any capacity standard.

The legal inquiry in New York focuses on a single point in time: the moment the document was signed. This is why generic statements about "stages of dementia" rarely decide a case. What decides it is evidence about the signer's specific understanding when pen met paper.

The Lucid-Interval Doctrine

New York recognizes the lucid interval — a period of mental clarity during which a person who is otherwise impaired regains sufficient understanding to act. A will or other document executed during a genuine lucid interval can be valid even if the person was incapacitated before and after. The burden of establishing that a lucid interval existed typically falls on the party seeking to uphold the document, and courts scrutinize such claims closely, looking at contemporaneous medical records, witness testimony, and the attorney's notes about the signing.

How a Will Is Challenged for Lack of Capacity in Surrogate's Court

When someone believes a will was signed by a person who lacked testamentary capacity, the challenge takes place in the Surrogate's Court of the county where the decedent lived. Lack of testamentary capacity is one of the principal grounds for a will contest in New York. Here is how the process generally works.

Burden of Proof

In a New York probate proceeding, the proponent of the will (usually the named executor) bears the initial burden of proving that the testator had testamentary capacity at the time of execution. Once the will is shown to have been duly executed with the required formalities, the objectant who claims lack of capacity must come forward with evidence to rebut the presumption of capacity.

The Role of Attesting Witnesses and the Attestation Clause

Under EPTL 3-2.1, a will must be signed by the testator in the presence of (or acknowledged before) at least two attesting witnesses, who must sign within 30 days of one another. A properly drafted attestation clause — reciting that the testator appeared to be of sound mind — and a self-proving affidavit add weight to the presumption of capacity and due execution. The testimony of the attesting witnesses about what they observed is often pivotal in capacity disputes.

SCPA 1404 Examinations

Before deciding whether to file formal objections, a potential objectant has the right under SCPA 1404 to examine the attesting witnesses and the attorney who supervised the will's execution (the attorney-draftsperson). These pre-objection depositions are a critical investigative tool: they allow counsel to probe the circumstances of signing, the testator's demeanor and statements, who was present, and whether there were signs of confusion or undue influence — all before committing to litigation.

Evidence That Decides Capacity Cases

New York capacity disputes are won and lost on contemporaneous proof. Courts commonly weigh:

• Medical and hospital records around the date of signing;
• The treating physician's or geriatric psychiatrist's observations;
• Testimony of the attorney-draftsperson and attesting witnesses;
• The testator's statements and behavior at the signing;
• Whether the new will represents a rational, explainable plan or an abrupt, unexplained change favoring a caregiver or recent acquaintance.

Lack of capacity claims frequently travel alongside claims of undue influence and, where a fiduciary is involved, breach of fiduciary duty. While distinct legal theories, they often arise from the same suspicious circumstances.

Practical Safeguards When Someone With Dementia Must Sign

If a person in the early stages of cognitive decline needs to sign a will, trust, or contract, careful planning can protect the document from later challenge — or, conversely, expose the lack of capacity if the document is improper. Prudent safeguards include:

• A contemporaneous capacity evaluation by the treating physician or, ideally, a geriatric psychiatrist, documenting that the signer met the relevant standard on the day of signing;
• Independent counsel who meets privately with the signer, outside the presence of any interested beneficiary, to confirm understanding and intent;
• A video recording of the execution ceremony in some cases, capturing the signer explaining their wishes in their own words;
• Careful attorney notes memorializing the testator's understanding of their property and family;
• Avoiding undue-influence red flags — the beneficiary should not select the attorney, drive the signer to the appointment, sit in on the meeting, or pay for the work.

For ongoing decision-making, families should also consider whether a durable power of attorney, health care proxy, and other advance directives were properly put in place before capacity declined, since these instruments themselves require capacity to execute.

Frequently Asked Questions

Can a person with dementia change their will in New York?

Possibly. If, at the moment of signing, the person understands that they are making a will, has a general sense of their property, and knows their natural beneficiaries, the new will can be valid under EPTL 3-1.1 and Matter of Kumstar — even with a dementia diagnosis. Abrupt changes that benefit a caregiver or new acquaintance, however, invite close scrutiny for both lack of capacity and undue influence.

Who can challenge a will signed by someone with dementia?

A person with legal standing — generally someone who would inherit if the challenged will were invalid, such as an heir under a prior will or a distributee under intestacy. The challenge is filed as an objection in the Surrogate's Court probate proceeding.

Is a contract signed by someone with dementia automatically void?

No. It is generally voidable, not automatically void. The party seeking to undo it must show the signer lacked the mental capacity to understand the nature and consequences of that particular transaction — a higher bar than the one used for wills.

Does a dementia diagnosis alone defeat a will?

No. New York courts focus on the testator's understanding at the time of execution, not on the diagnosis generally. Many people with early or moderate dementia retain testamentary capacity, and the lucid-interval doctrine can validate a will signed during a period of clarity.

What is the difference between testamentary capacity and contractual capacity?

Testamentary capacity (for wills) is the lowest standard — understanding the act of making a will, one's property, and one's beneficiaries. Contractual capacity is higher because contracts involve understanding ongoing, reciprocal rights and obligations. A person can have one without the other.

Speak With a New York Estate Litigation Attorney

Capacity disputes are fact-intensive and time-sensitive. Whether you are trying to protect a loved one's will from challenge, or you suspect a will, trust, or contract was signed by someone who lacked capacity, prompt action — including securing medical records and pursuing SCPA 1404 examinations — can be decisive.

The Law Offices of Albert Goodwin handles will contests, trust disputes, and capacity litigation in Surrogate's Courts throughout New York. We have offices in New York City, Brooklyn, and Queens. Call 212-233-1233 or email [email protected] to discuss your situation.

Reviewed by Albert Goodwin, Esq., founder of the Law Offices of Albert Goodwin, a New York estate, trust, and guardianship litigation firm. Mr. Goodwin is admitted to practice law in New York and has represented clients in will contests, capacity disputes, and Surrogate's Court litigation across New York City and Long Island.

Last reviewed and updated: June 2024. This article is for general informational purposes and is not legal advice. Outcomes depend on the specific facts of each case.