Also known as: mental capacities · mental competence · mental competency
Written by attorneys — see sources below.
The cognitive ability required to understand the nature and consequences of a legal act or transaction.
Michael Miller, recovering from surgery and on strong pain medication, attempted to assign his entire investment portfolio to a speculative fund. Family members later challenged the transfer. The assignment is invalid because Michael lacked the mental capacity to make the donative transfer at the time of execution.
Meredith Maxwell consumed hard cider and marijuana throughout the afternoon before participating in a marriage ceremony. She required repeated prompting to recite her lines and laughed inappropriately during the vows. The marriage is invalid because Meredith lacked mental capacity to understand and agree to the marriage at the time of the ceremony.
Miles Montgomery executed an irrevocable deed transferring his primary income-producing building while living in assisted living and relying on rental income. He occasionally confused family members and tenants during the transaction. The deed is invalid because Miles lacked the mental capacity to understand the gift's effect on his future financial security and that of his dependents.
Mason McCarthy, adjudicated incompetent with the mental capacity of an 18-month-old, executed a deed conveying real property while under guardianship. The guardian later sought to set aside the deed. The conveyance is void because Mason lacked the mental capacity to understand the nature and consequences of the transaction at the time of execution.
Joshua DeShaney was born in 1975. In 1980, a Wyoming court granted his parents a divorce and awarded custody of Joshua to his father, Randy DeShaney, who then moved with the child to Winnebago County, Wisconsin. In January 1982, the Winnebago County Department of Social Services became aware that Joshua might be a victim of child abuse after he was admitted to a local hospital with multiple bruises and abrasions. The examining physician notified DSS. A caseworker interviewed Randy DeShaney and visited the home, observing suspicious injuries on Joshua's head, but concluded there was insufficient evidence of abuse to retain him in court custody and returned him to his father while recommending counseling and preschool enrollment. Over the next two years, Joshua was repeatedly treated for suspicious injuries at local hospitals, with physicians notifying DSS on multiple occasions. Caseworkers conducted regular visits, noted additional injuries, received reports from emergency room personnel and neighbors, and at one point convened a Child Protection Team that decided against retaining custody, yet consistently returned Joshua to his father's care after determining insufficient evidence existed for court intervention. In March 1984, Randy DeShaney beat Joshua so severely that the child fell into a coma and suffered permanent brain damage requiring lifelong institutionalization for profound mental retardation. Randy DeShaney was later tried and convicted of child abuse. Joshua and his mother filed suit under 42 U.S.C. § 1983 against Winnebago County, its Department of Social Services, and two social workers in the United States District Court for the Eastern District of Wisconsin, claiming a deprivation of liberty without due process. The district court granted summary judgment for the respondents. The Court of Appeals for the Seventh Circuit affirmed. The Supreme Court granted certiorari.
View caseMegan Moore, while experiencing an acute psychotic episode, signed a written confession during police interrogation. Defense counsel later moved to suppress the statement. The confession is inadmissible because Megan lacked the mental capacity to understand the nature and consequences of the waiver at the time of signing.
Monte Durham was convicted of housebreaking by the District Court of the District of Columbia sitting without a jury. The prosecution proceeded on a charge arising from an incident on July 13, 1951, in which Durham was found in a house. Durham's history included discharge from the Navy in 1945 at age seventeen following a psychiatric examination revealing a profound personality disorder rendering him unfit for service. In 1947 he pleaded guilty to violating the National Motor Theft Act and was placed on probation for one to three years. In January 1948, as a result of a conviction in the District of Columbia Municipal Court for passing bad checks, the District Court revoked his probation and he commenced service of his Motor Theft sentence. His conduct within the first few days in jail led to a lunacy inquiry in the Municipal Court where a jury found him to be of unsound mind. Upon commitment to St. Elizabeths he was diagnosed as suffering from 'psychosis with psychopathic personality.' He experienced multiple discharges and readmissions to St. Elizabeths between 1949 and 1951, including a conditional release in June 1950 that he violated, and a further lunacy finding in 1951. Following the July 1951 housebreaking, Durham was indicted in October 1951 and adjudged of unsound mind based on psychiatrists' affidavits diagnosing psychosis with psychopathic personality. He underwent subshock insulin therapy during a six-month commitment ending in February 1953, after which Dr. Silk certified him mentally competent to stand trial and able to assist counsel. At the ensuing trial, the prosecutor expressed a plan to allow Durham to raise an insanity defense on this charge. The court accepted waivers of jury trial and additional competency proceedings despite Durham's expressed desire for further hospitalization. Testimony included that of Durham's mother regarding his post-May 1951 behavior and a psychiatrist who examined him in September 1951 and opined on his mental condition around the time of the offense. The trial court found the defense of insanity not established under the prevailing standards. The appeal reached the United States Court of Appeals for the District of Columbia Circuit.
View caseMatthew Martinez, operating a group home, signed a long-term commercial lease while suffering from documented cognitive impairment. The landlord later sought enforcement. The lease is voidable because Matthew lacked the mental capacity to understand the nature and consequences of the contractual obligation at the time of execution.
In July 1980, respondent Jan Hannah purchased a building at 201 Featherston Street in Cleburne, Texas. Hannah intended to lease the property to Cleburne Living Center, Inc. (CLC) for use as a group home. The home would house thirteen mentally retarded men and women under constant staff supervision. The building contained four bedrooms and two baths, and CLC planned to add a half bath while complying with all applicable state and federal regulations for an Intermediate Care Facility for the Mentally Retarded. The site lay in an R-3 Apartment House District. The city's zoning ordinance permitted apartment houses, boarding houses, hospitals, and nursing homes in that district without special permission. However, the ordinance required a special use permit, renewable annually after a public hearing, for hospitals for the insane or feeble-minded. The city classified the proposed group home as a hospital for the feeble-minded and informed CLC that a permit was required. After a public hearing, the City Council voted three to one to deny the application. CLC and its prospective residents filed suit in federal district court against the city and its officials. They alleged that the ordinance and its application discriminated against the mentally retarded in violation of the Equal Protection Clause. The district court upheld the ordinance and the denial. It found that the council's decision was motivated by the residents' mental retardation yet rationally related to legitimate interests such as neighborhood safety and property values. The Court of Appeals for the Fifth Circuit reversed, holding that mental retardation is a quasi-suspect class and that the ordinance was invalid both facially and as applied. The Supreme Court granted certiorari to review the equal protection issues raised by the zoning ordinance and its application to the proposed group home.
View caseA person lacks capacity to contract when mental illness or intellectual disability prevents reasonable understanding of the transaction's nature and consequences. The resulting contract is voidable at the option of the impaired party if the other side had reason to know of the condition. Courts assess capacity at the time of contracting and focus on functional ability rather than formal adjudication alone.
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Capacity is determined at the precise moment of the marriage ceremony. Intoxication from alcohol or drugs that prevents understanding the actions and agreement renders the marriage invalid. Visible signs of impairment such as disorientation or inability to follow instructions establish lack of capacity.
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The donor must possess the mental capacity necessary to make or revoke a will and must also understand the gift's effect on the donor's future financial security and that of any dependents. Medication, recent surgery, or reliance on the transferred assets for support can demonstrate failure to meet this standard.
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Yes. Once a court adjudicates a person incompetent and places property under guardianship, the ward lacks capacity to incur contractual duties regarding that property. Any later agreement is void rather than merely voidable.
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…in a special class is not presumptively irrational. The differences between mentally retarded persons and those with greater mental capacity are obviously relevant to certain legislative decisions. An impartial lawmaker — indeed, even a member of a class of persons defined as mentally retarded — could rationally vote in favor of…