Can a Person with Alzheimer’s Disease Sign Legal Documents?

By Bernard A. Krooks, Certified Elder Law Attorney 

Approximately 6.5 million people in the United States have Alzheimer’s Disease. In fact, more than 10% of people age 65 and over are living with Alzheimer’s. Alzheimer’s is a progressive disease that gets worse over time and there currently is no cure. We have written extensively in this column about the importance of getting your affairs in order and taking care of your estate planning before something happens to you. By doing so, you will make things much easier for you and your family. So, what happens if someone is diagnosed with Alzheimer’s, and they have not yet done their estate planning? Is it too late? That depends. 

A certain level of capacity is necessary in order to sign legal documents. Someone who is in the later stages of Alzheimer’s probably does not have the requisite capacity to sign legal documents. However, a person in the early stages of Alzheimer’s or with a diagnosis of dementia may very well be able to sign legal documents. 

For these purposes, capacity is typically analyzed situationally. That is, the question will be answered differently depending on the nature of the document and the circumstances of the signing. The general rule: the signer has to have sufficient understanding to know what the document is, and the effect of the signing. 

Here are a few examples: 

• Ability to sign a contract. 

• Understanding of a power of attorney, which might give the authority to another person to make financial decisions for you. 

• Capacity to sign a trust. 

• Capacity to get married (which is, after all, a specialized kind of contract). 

• Ability to make medical decisions — including refusing medication, or either seeking or declining mental health treatment. 

Although each of these situations will be evaluated differently, we can offer some general thoughts: 

• The capacity level required to sign a trust is generally thought to be similar to the level of capacity to sign a contract. 

• The capacity to sign a will is generally considered the lowest level of capacity required to sign any legal document in New York. 

• There are few legal ways to determine capacity in advance. Some argue whether it is a legal or medical determination. Challenges to capacity are almost always initiated after the signing is completed — and often after the signer has died or becomes mentally incapacitated. That means that evidence of capacity (or lack of capacity) is often being reconstructed after the fact. 

It’s also important to remember that we are writing here about capacity, and not necessarily about the validity of documents signed by someone with Alzheimer’s. It is entirely possible that although someone with Alzheimer’s has the legal capacity to execute a new will, they were unduly influenced by someone else when signing their will. There is a difference between capacity on the one hand and undue influence on the other. Alzheimer’s might make a person incapable of signing a document, or their capacity may be sufficient to sign. But that same person might be more susceptible to undue influence because they have Alzheimer’s. 

The following example may help explain what we mean:  an elderly widower, living alone, has a diagnosis of Alzheimer’s. He is nonetheless charming, witty, and perfectly able to discuss his wishes. He can recall the names of his three children and his seven grandchildren. He can report their ages, the cities they live in, and their careers (or status as students) — and he is mostly correct, though sometimes his information is two or three years out of date. 

This gentleman’s daughter lives in the same city and is the one who oversees his living arrangements and care. She does his shopping, hires people to check on him daily, takes him to doctors’ appointments, writes out his checks (he still signs them), and otherwise helps out. She also talks to him endlessly about how his other two children don’t deserve to end up with his house and bank accounts, how she really ought to be the one who benefits from his estate, and how his late wife (her mother) always wanted her to inherit everything. Eventually, he agrees to sign a new will and trust, mostly to stop her constant harangues. 

Did he have the capacity to sign the new estate planning documents? On the facts as we’ve given them here, probably yes. Was he unduly influenced? Very likely. Was that influence facilitated (and the proof made easier) because of his Alzheimer’s? Absolutely. 

When did the daughter’s behavior cross the line? The legal system isn’t actually very helpful, since the answer is defined in a circular fashion. Her influence was “undue” when it resulted in her wishes being substituted for his. It was not necessarily objectionable (at least not legally) when she told him what she wished he would do, what her mother had wanted, or what was fair. But at some point, she may well have turned ordinary familial influence into “undue” influence. 

As you can see, this area of the law is quite complex. By working with a competent estate planning attorney, you can increase the likelihood that your wishes will be carried out if you become incapacitated or pass away.

Bernard A. Krooks, Esq., is a founding partner of Littman Krooks LLP and named 2021 “Lawyer of the Year” by Best Lawyers in America® for excellence in Elder Law and has been honored as one of the “Best Lawyers” in America since 2008. Call (914-684-2100) or visit the firm’s website at