This is not a medical blog, but medicine and the law interact extensively when it comes to determining (or challenging) a person’s legal capacity.  To prove lack of capacity requires evidence of a mental defect, such as dementia or Alzheimer’s disease.  Alzheimer’s also plays a role in proving a weakness of mind—required for undue influence.

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The problem is that dementia and Alzheimer’s is often overlooked, misdiagnosed, or not diagnosed at all even though the conditions may be present.  For example, Alzheimer’s patients can go ten to fifteen years with the disease before showing any outward symptoms.  In part, a lack of diagnoses stems from the difficulty medical science has had determining when a person has Alzheimer’s disease.

In a recent report by CNN, as reported by Dr. Sanjay Gupta, detecting the presence of Alzheimer’s disease may be possible by looking into a person’s eyes.  Dr. Gupta explains that Alzheimer’s can be detected by sticky plagues in the brain made up of proteins called “beta amyloid.”  But these proteins are very difficult to detect in the brain without doing invasive surgery.  However, researchers now believe that the same proteins found in the brains of Alzhemer’s patients may also be present in the eyes—at the back of the retina.  They are now conducting a clinical trial to see if the eye test can identify patients who are starting to develop Alzheimer’s disease.

Better diagnoses means better understanding of the disease, and a chance to address the problem before it progresses.  For the legal community, earlier diagnosis provides a better (and more accurate) idea of when an elder becomes incapacitated or susceptible to undue influence because of a weakness of mind. 


In California, proving a weakness of mind or lack of capacity requires medical evidence of a mental defect (see Probate Code Section 811).  We have come across many elders who are obviously susceptible to undue influence, yet they have no medical diagnosis of a mental defect.  As a result, their mental condition cannot be established in a Court proceeding.  By having a more accurate picture of a person’s mental capacity, the true state of their decision making abilities can be determined.  This can be a huge breakthrough to protecting elders and ensuring their true desires are reflected in their Trusts and Wills.

They say the eyes are the window to the soul, but they may also be the window to better mental health too.

(For more on signs of Alzheimer’s, see this CNN article: The 10 warning signs of Alzheimer’s.)

Lack of capacity is probably the most used concept in trying to overturn a California Will or Trust.  And while nearly ever Trust or Will contest lawsuit contains an undue influence allegation, undue influence is usually minimized or even ignored altogether at trial.  In this vide, Keith A. Davidson discusses how both concepts can be used to overturn a California Will or Trust.  For those viewing this blog by email subscription, you can click on the title for a link to the video.

See Video Below:

Stewart R. Albertson discusses how undue influence is used to overturn a California Will or Trust.  There are two ways to prove undue influence in California, either directly or by shifting the burden of proof onto the opposing party.  Stewart describes the basic concepts.  For those viewing this blog by email subscription, you can click on the title for a link to the video.

I’ve blogged before about using the concept of undue influence to overturn a California Will or Trust.  But knowing the definition of undue influence is only the first step.  To make the concept of undue influence useful, you have to know how to prove the existence of undue influence in a Court of law.  That can be trickier than it sounds.  Let’s walk though the primary options for proving undue influence in California: 

Under California law, undue influence consists of:

An Example of Undue Influence: 

It is usually easy to spot undue influence. For example, Jane has three children, namely, John, Jerry, and Jack. Jane is living with John at the end of her life, and relies on John for her daily living needs. John does not like his brothers Jerry and Jack. Six weeks before Jane dies, John drives his mother to an attorney to change her California Will or Trust, which disinherits Jerry and Jack. Now John goes from getting one-third of his mother’s Will or Trust to getting 100 percent. The question: Did John exercise undue influence over Jane? Most likely, yes. But how do you prove undue influence under California law? 

How to Prove Undue Influence under California Law: 

There are two primary ways to prove undue influence under California law—by either (i) shifting the burden of proof to John, in the example above, so he then has to prove an absence of undue influence, or (ii) by Jerry or Jack proving directly that John exercised undue influence over their mother. If at all possible, it is best to shift the burden to John to prove he did not exercise undue influence over Jane because it can be very difficult to prove the absence of something. If you don’t have facts that shift the burden of proof to John, then Jerry and Jack will have the burden of proving the existence of undue influence directly.

 How to Shift the Burden of Proof in an Undue Influence Case:

How do you shift the burden of proof to John so that he carries the burden to prove he did not exercise undue influence over Jane? Under California law there is a presumption of undue influence that arises if you can establish three facts:

  • Confidential Relationship: Jerry and Jack must prove that John had a “confidential relationship” with Jane, which can consist of John being Jane’s trustee, or agent under a power of attorney, or conservator, or perhaps, simply being Jane’s son.
  • Active Participation: John must have “actively participated” in the preparation or execution of the Will or Trust.
  • Undue Benefit: John must receive an “undue benefit” by way of the new Will or Trust.  

You can prove each of these facts where John (i) is the Executor or Trustee of Jane’s Will or Trust, (ii) arranged to have an attorney draft the new Will or Trust for Jane to sign, and (iii) where John’s interest in the Jane’s Will or Trust increases from one-third to a higher amount. 

Once these facts are proven, there is a presumption that John exercised undue influence over Jane causing her to create the new Will or Trust; and the burden of proof shifts to John to prove the absence of undue influence, which is not easy for John to do under this fact scenario. Essentially John has to prove a negative—i.e. that undue influence did not occur. 

 How to Prove Undue Influence Directly:

If you can’t prove facts shifting the burden of proof to John, you must prove undue influence directly. Circumstantial evidence is enough to prove undue influence. Here are the most likely facts you need to prove undue influence directly:

 Disinheriting a child: Provisions that are unnatural, cutting off from any substantial bequests the natural objections of the decedent’s bounty. When Jane disinherits Jerry and Jack, that is disinheriting her children, an unnatural act, which can indicate undue influence.

 Contradicting decedent’s former estate plan: Dispositions at variance with the decedent’s intentions, expressed before the document’s execution. If Jane had a previous Will or Trust that treated her children equally, but a new Will or Trust (or Amendment) contradicts the former Will or Trust (or Amendment), this can add to the conclusion that Jane was unduly influenced.

 Opportunity to control decedent: Relations existing between the chief beneficiaries and the decedent that afforded the former an opportunity to control the testamentary act. If Jane relied on John for her daily living needs, this can add to the conclusion that Jane was unduly influenced.

 Poor mental and physical condition: A testator whose mental and physical conditions are such as to permit a subversion of her freedom of will; and if there is evidence the testator had a weakened state of mind it is easier to demonstrate the pressure from another overcame the testator’s free will.

 Sudden negative shift in attitude: Under California law, courts may infer that Jane’s sudden negative shift in attitude toward Jerry and Jack was caused by John’s poisoning Jane’s mind because the court can find no other rational explanation.

 Decedent’s advanced age: A Will or Trust creator of advanced age at the time a document is signed adds to the conclusion the testator was unduly influenced.

 History of mental deficits: A Will or Trust creator with a history of mental deficits adds to the conclusion the testator was unduly influenced. California Probate code section 811 outlines the likely areas of mental deficits.

 History of Dementia or Alzheimer’s disease: A Will or Trust creator with a history of Dementia or Alzheimer’s Disease adds to the conclusion the testator was unduly influenced.

Testator under conservatorship: A Will or Trust creator that is under a court ordered conservatorship adds to the conclusion the testator was unduly influenced. 

The more of these facts you can establish, the easier it is to prove undue influence directly.

There you have it—a big picture view of how to prove undue influence cases under California law. In future blog posts, I will treat in further detail (i) the burden shift for undue influence cases, and (ii) proving undue influence directly.

The concept of “undue influence” can be used to invalidate a Will or Trust. What is undue influence? According to the California legislature “undue influence” is the taking of an unfair advantage of another’s weakness of mind. In a word: coercion. For example, a caretaker befriends an elderly person and takes over the elder’s financial affairs, such as writing checks, paying bills, etc. Even though the elderly person already has a Will and Trust leaving all of her property equally to her two children, the caretaker takes advantage of his position of trust and convinces the elderly person to create a Will and Trust leaving everything to the caretaker and disinheriting the children. The Will and Trust that the elderly person creates under these circumstances does not reflect the elder’s intent (because she wanted her assets to pass to her children), rather it reflects the intent of the caretaker. The children can then sue after the elderly person’s death and challenge the validity of the Will and Trust based on Undue Influence of the caretaker.

Generally, the objectors of a Will or Trust (such as the children in the above example) have the burden of proving by a preponderance of the evidence that the caretaker exercised undue influence over the decedent.  But that burden of proof can shift to the caretaker if certain facts are present.  Once shifted, the caretaker then has to prove that he did NOT unduly influence the elderly person, and he must likely prove this by clear and convincing evidence (which is a higher standard).  This is nearly impossible for the caretaker to prove because he must prove a negative—that undue influence was not present—a hard task to accomplish.  Therefore, shifting the burden is critical and nearly always fatal once accomplished.

To shift the burden of proof to caretaker, the children must prove the following three elements:

  • Caretaker and Mom had a confidential relationship;
  • Caretaker participated in the creation of the changed Trust and Will; and
  • Caretaker unduly profited from the changed Trust and Will.

Under the above example, the burden would likely shift to the caretaker because there was a confidential relationship (since Mom was dependent on the caretaker for support and maintenance), we may have facts that he participated in the Will creation (we did not say that above, but it is a common occurrence), and the caretaker unduly profited by receiving all of the estate. 

What’s the likely outcome? More than likely, with the proper presentation at trial, the Probate Court will invalidate Mom’s Will and Trust and restore children’s inheritance.