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Lucid Intervals and Estate Planning

Updated: May 20, 2023

While the “Lucid Interval Doctrine” may sound intimidating—as law often does—this fancy term only describes what many of us see in our aging loved ones every day. Sometimes, Mom or Dad is razor sharp…and sometimes, not so much. The lucid interval doctrine acknowledges this ebb and flow of cognitive functioning.[1] The law states that a person diagnosed with a neurodegenerative disorder, such as Alzheimer’s Disease, may still possess legal capacity to execute estate planning documents during a lucid interval.[2] A lucid interval is a moment in which comprehension returns.[3]


(For more information about legal capacity, check out our article Capacity and Estate Planning.)

The lucid interval doctrine tells us that if a client with diminished capacity satisfies the legal requirements of capacity at the moment of signing, then the document is valid.[4] Legal capacity is determined at the moment of signing.[5] Let’s say that again: Legal capacity is determined at the moment of signing.[6] A client may experience diminished cognitive functioning before or after the execution of the document. However, at the moment of signing, if the client possesses the requisite level of legal capacity for that transaction, then the law recognizes the validity of the document.[7]

You don’t need to live in the state of Kentucky or understand case law to appreciate the following quote that captures the essence of the lucid interval doctrine. Chief Justice Stephens of the Supreme Court of Kentucky penned a perfectly straightforward explanation of lucid intervals with regard to a Last Will & Testament.[8] In his 1998 opinion, he wrote:

“When [a person creating a Last Will & Testament] is suffering from a mental illness

which ebbs and flows in terms of its effect on [their] mental competence, it is presumed

that [person] was mentally fit when the will was executed. This is commonly referred

to as the lucid interval doctrine. …Alzheimer’s is a disease that is variable in its effect

on a person over time. It is precisely this illness with which the lucid interval doctrine

was designed to deal. By employing this doctrine, citizens…who suffer from a debilitating mental condition are still able to dispose of their property.”[9]


How does the lucid interval doctrine apply to you or a loved one who experiences mental decline? Foremost, if the person with diminished capacity hasn’t executed their estate planning documents—or if they wish to change existing documents—then now is the time to schedule a consultation with a licensed elder law attorney in your state. Time is of the essence because cognitive functioning may further decline if you wait. Why an elder law attorney? An attorney who specializes in elder law keenly understands the possibilities within the lucid interval doctrine. All isn’t necessarily lost if an individual has been diagnosed with a neurodegenerative disease. Within the law, there may be a window of opportunity.


Until next time…Plan Early. Plan Often. Plan Well.


Beach Barrister is NOT a law firm. We are an educational forum. We do NOT legally counsel individuals based upon their specific life circumstances or planning goals.


Beach Barrister is NOT a substitute for legal counsel. We highly encourage every viewer of this site to seek a local, licensed, reputable attorney to assist you with your state-specific laws, planning goals, and execution of documents.

[1] “When a testator is suffering from a mental illness which ebbs and flows in terms of its effect on the testator's mental competence, it is presumed that the testator was mentally fit when the will was executed. This is commonly referred to as the lucid interval doctrine.” Bye v. Mattingly, 975 S.W.2d 451, 456 (Ky. 1998). [2] Id.; “A Neurodegenerative Disease is a condition that affects neurons in the brain, causing symptoms such as memory loss, moodiness, anxiety, depression, and agitation.” Kaizen Brain Center, About Neurodegenerative Disease, https://www.kaizenbraincenter.com/about-neurodegenerative-disease (last viewed February 8, 2023). [3] “The terms “lucid moment” or “lucid interval” do not describe a moment when the testator was not patently delusional. A “lucid moment” is a period of time during which the testator returned to a state of comprehension and possessed actual testamentary capacity.” American Red Cross v. Estate of Haynsworth, 708 So. 2d 606 (Fla. 3d DCA 1998). [4] “A person who is mentally incapacitated part of the time but who has lucid intervals during which he or she meets the standard for mental capacity can, in the absence of an adjudication or statute that has contrary effect, make a valid will or a valid inter vivos donative transfer, provided such will or transfer is made during a lucid interval.” Jesse Dukeminier & Robert H. Sitkoff, Wills, Trusts, and Estates 270 (Vicki Been et al. eds., Wolters Kluwer Law & Business 9th ed., 2013). [5] “Capacity is required at the time the will was executed.” ABA Commn. On L. & Aging & Am. Psychological Assn., Assessment of Older Adults with Diminished Capacity: A Handbook for Lawyers 5 (2005).

[6] “A study of the pertinent cases reveals that the precise condition of the testator's mental health at the time he executed his will may be established in more ways than one.” Italics added for emphasis. In re Estate of Zimmerman, 84 So. 2d 560, 562 (Fla. 1956). [7] “What the condition of his mental health was when he executed his will…was the immediate problem confronting the probate court. "Before hand" and "afterward" proof of the testator's mental behavior would certainly be a lead to this and would be proper for the court to consider in making up his judgment as to whether or not the will was made during a lucid interval as appellants contend or whether it was made when the mind was incompetent to do so.” Id.

[8] Bye v. Mattingly, 975 S.W.2d 451, 456 (Ky. 1998). [9] Id. Brackets inserted to enhance reader understanding. A “testator” is the person who creates the Last Will & Testament. The original opinion reads, “When a testator is suffering from a mental illness which ebbs and flows in terms of its effect on the testator’s mental competence, it is presumed that the testator was mentally fit when the will was executed. This is commonly referred to as the lucid interval doctrine. …Alzheimer’s is a disease that is variable in its effect on a person over time. It is precisely this illness with which the lucid interval doctrine was designed to deal. By employing this doctrine, citizens of the Commonwealth who suffer from a debilitating mental condition are still able to dispose of their property.” Italics added for emphasis.

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