Can You Prove Lack of Testamentary Capacity in California?

Can you overturn a will or trust because your mother had dementia when she signed it? Sometimes. But the diagnosis alone will not do it. Testamentary capacity in California is a low bar, the law presumes she had it, and you carry the burden of proving she did not (Probate Code §§ 810, 8252).

The question a judge asks is narrow. Not whether she had dementia, but whether, at the moment she signed, she understood what the document was, what she owned, and who her family was (Probate Code § 6100.5).

Here's the thing families get wrong. They collect proof that Dad was sick. The court wants proof of what Dad understood on one particular day. Different project, and one with a deadline; the deadline wizard tells you how many days are left.

How hard is it to prove lack of testamentary capacity in California?

California law presumes that every person has the capacity to make decisions (Probate Code § 810). In a will contest, the person attacking the will must prove lack of capacity (Probate Code § 8252). Trusts are no different. In Doolittle v. Exchange Bank the Court of Appeal said a contestant carries a "heavy burden." The standard for testamentary capacity, in words that court borrowed from an earlier case, is "exceptionally low."

The law wants people to leave their property as they choose, even when they are old, sick, or forgetful. A person with a mental or physical disorder may still be capable of executing wills or trusts. A diagnosis by itself is not enough to prove incapacity (Probate Code §§ 810, 811).

So a Kaiser chart with a dementia diagnosis on it is a starting point, not a verdict. What wins is evidence of a specific deficit, tied to the specific decision, on the specific day (Probate Code § 811). That sentence is the whole case.

What is the legal test for capacity to make a will in California?

Lack of testamentary capacity is the legal name for the claim. For a will, the test is Probate Code § 6100.5: a person is not competent to make a will if, at the time of making it, she cannot do any one of three things.

• Understand the nature of the testamentary act. Know that she is signing a document that says who gets her property when she dies.
• Understand and recollect the nature and situation of her property. Know, roughly, what she owns: the house in Sunnyvale, the accounts.
• Remember and understand her relations to her descendants, spouse, and parents, and to the people the will affects. Know who her children are, and that the document cuts one of them out.

A will also fails if delusions or hallucinations from a mental health disorder caused her to leave property in a way she otherwise would not have (Probate Code § 6100.5). Picture the parent convinced a child is stealing from her, who disinherits that child for it. The delusion has to drive the gift.

What does not count? The courts have said for decades that "old age, feebleness, forgetfulness," and even "failure to recognize old friends or relatives" do not, by themselves, prove a lack of testamentary capacity (Andersen v. Hunt, quoting earlier cases). Mom repeating herself is an undue influence fact, not yet a capacity case. Our guide to how to contest a will in California covers the procedure for raising either one.

What capacity is needed to make or amend a trust in California?

Trusts and contracts are judged under Probate Code § 811 and its neighbors, Probate Code §§ 810 through 812. Probate Code § 811 lists the mental functions a court looks at: alertness, orientation, memory, communication, recognizing familiar people, reasoning, planning, thought processes such as delusions, and mood. A finding of incapacity needs a deficit in at least one of them that correlates with the decision in question (Probate Code § 811). The deficit counts only if it significantly impairs her ability to understand and appreciate the consequences of that particular act.

Probate Code § 812 adds that she must grasp the decision's rights, duties, probable consequences, risks, benefits, and alternatives.

The Court of Appeal in Andersen v. Hunt read those sections together and drew the sliding scale: more complicated decisions require greater mental function, less complicated decisions require less. The same 84-year-old with the same chart might have capacity for a one-page amendment and not for a restated trust with sub-trusts and estate tax planning.

Which capacity test applies to a trust amendment?

In Andersen v. Hunt, a father who had suffered a stroke amended his trust to leave 60 percent of his estate to his long-term partner. The amendments did nothing but set percentages, yet the probate court threw them out under the tougher Probate Code §§ 810 to 812 standard. The Court of Appeal reversed. An amendment that "in its content and complexity, closely resembles a will or codicil" gets the will test, and the amendments stood.

In Lintz v. Lintz, a Monterey County case, a wealthy retired developer signed a string of amendments favoring his third wife, then a new trust her lawyer prepared. Those documents dealt with community property, gave her income for life, and created several trusts with estate tax planning. Documents that complex, the court held, get the sliding scale of Probate Code §§ 810 through 812, not the lower will test.

Does a dementia diagnosis prove my parent lacked capacity when signing?

No, not by itself. The will statute says at the time of making the will (Probate Code § 6100.5). The cases say the same about trusts: the question is the signer's "mental state in relation to a specific event" (Andersen v. Hunt). A diagnosis in January does not prove incapacity in June. A good day in June does not rescue a document signed on a bad day in April.

Then there is the lucid interval rule. When a person has a mental disorder with lucid periods, the law presumes the will was made during one of them. A finding of incapacity stands only if that presumption is overcome (Andersen v. Hunt, quoting earlier cases). The court may weigh "the frequency, severity, and duration of periods of impairment" (Probate Code § 811).

Evidence from the week of the signing is worth ten times evidence from the year before. A nurse's note from the day before. The lawyer's notes from the signing meeting. Those are the exhibits.

What evidence proves lack of testamentary capacity in Santa Clara County?

Capacity cases here are decided by a judge in the probate court in San Jose. There is no jury (Probate Code §§ 825, 8252).

• Medical records. In this county that means Stanford, Kaiser, El Camino, Good Samaritan, and Valley Medical. You want the visit notes from the months around the signing, not just the diagnosis line. A Mini-Mental State Exam score or a nurse's note that the patient did not know the year is a dated deficit under Probate Code § 811.
• The drafting lawyer's file. Who booked the appointment, who sat in the room, what your parent said. The other side prepares for this. In Doolittle v. Exchange Bank the mother signed a trust moving most of her $8.5 million estate to her gardener and a group of friends and caregivers. Around the same time she had a neuropsychologist sign an affidavit that she had capacity that day, and she obtained six certificates of independent review from a separate lawyer. The court let the trustee spend trust money defending the amendment.
• Witnesses. The notary, the neighbor who visited that week, the home health aide. A caregiver's daily log is gold.
• Conservatorship files. Conservatorship cases are heard in the same probate court, and that file is dated evidence. But even a person under a guardianship can make a valid will unless the incompetence continued at the time of signing (Andersen v. Hunt, quoting older cases).

Can I claim both lack of capacity and undue influence?

Yes, and you usually should. Almost every capacity case is also an undue influence case; plead both. The undue influence statute lists impaired cognitive function, illness, isolation, and dependency as evidence of a victim's vulnerability (Welfare and Institutions Code § 15610.70; Probate Code § 86 adopts the same definition). So the chart that falls short on capacity can still carry that factor. Lintz is the proof: the trial court found the husband had capacity and voided his trust documents anyway, for undue influence. Our guide to undue influence in California covers the factors and the presumptions. If a caregiver or one child ended up with everything, our guide to a sibling or caregiver who got everything explains the presumption that can shift the burden to them.

What should you do if you suspect your parent lacked capacity?

1. Find the document and its date. The signing date is the center of the case.
2. Calendar the deadline today. A lack of capacity claim is a direct contest (Probate Code § 21310). After a trustee's notice you have 120 days to file it (Probate Code § 16061.8). For a will, object before it is admitted or petition to revoke within 120 days after (Probate Code §§ 8250, 8270). A late contest counts as one filed without probable cause and can trigger a no-contest clause (Probate Code § 21311; Meiri v. Shamtoubi). Our deadline guide has every clock.
3. List every doctor, hospital, and clinic that saw your parent in the year around the signing.
4. Write down what you saw, with dates. The day she did not know your name. Who drove her to the lawyer.
5. Identify the people in the room: the lawyer, the notary, the witnesses, the caregiver. Give the names to counsel.
6. Talk to a lawyer this week. The clock is running, and the other side may already have a file built.