The Psychological Assessment of Testamentary Capacity, Contractual Capacity, Undue Influence, and the Capacity to Make Medical Decisions

By Teo Ernst, PsyD, ABPP

This article provides a conceptual framework for understanding legal capacity and describes the components and legal basis of a psychological assessment of testamentary capacity, contractual capacity, undue influence, and the capacity to make medical decisions. It may serve as a reference for attorneys to identify the key aspects of an effective capacity evaluation, and to prepare for cross-examination of opposing experts.

Capacity – Foundational Concepts

Within legal proceedings, capacity is a legal criterion describing what an individual is required to do, during a specific act, in a specific context. The legal criteria for various capacities (e.g. testamentary capacity, adjudicative capacity, etc.) are based upon legal standards articulated in the penal code, probate code, and other relevant sources of law.

Critical to the assessment of capacity is an analysis of the examinee’s ability to perform functional abilities relevant to the capacity in question. Functional abilities may be defined as what a person knows, understands, and can do. For instance, a functional ability relevant to testamentary capacity is the ability to understand the nature of one’s property.

Importantly, an individual’s incapacity may either fluctuate or remain constant depending on the cause of her incapacity. For instance, while progressive dementia may result in constant incapacity, the transient nature of delirium may result in fluctuating episodes of incapacity.

The degree of ability required to demonstrate capacity is not consistent across all situations, but instead varies according to the complexity of the act in question. More complex acts require higher levels of ability. For instance, the functional abilities necessary to consent to a routine medical procedure, such as a blood draw, are lower than the functional abilities necessary to consent to a highly complex neurological surgery.

Although a psychiatric or medical diagnosis may cause incapacity, diagnosis in and of itself does not equate to capacity. As noted above, capacity is based upon an individual’s ability to demonstrate functional abilities relevant to a given legal standard. Individuals with the same diagnosis may demonstrate radically different levels of functioning, and thus demonstrate divergent levels of capacity. For instance, research by Warner (2006) found that 76% of participants with mild to moderate dementia lacked the capacity to give informed consent to engage in medical research, while the remaining individuals with the same diagnosis retained this capacity. Thus, although the presence of dementia may sometimes cause incapacity to consent to medical research, the presence of this diagnosis alone does necessitate the presence of incapacity.

Grisso’s Five-Step Model for the Assessment of Capacity:

Thomas Grisso has provided an elegant model of assessing legal capacity, which serves as a foundational model of practice within the field of forensic psychology. Grisso identifies five components of a capacity evaluation: the Functional Component, Causal Component, Interactive Component, Conclusory Component, and Remediative Component.

During the Functional Component, the forensic psychologist determines which functional abilities are relevant to a given capacity based upon the appropriate legal standard. For instance, during the assessment of testamentary capacity in California, Probate Code 6100.5 states that an individual lacks the capacity to make a will if, at the time of making the will, he does not have sufficient mental capacity to understand the nature of the testamentary act, understand and recollect the nature and situation of his property, or remember and understand his relation to living descendants, spouses, parents, and those whose interests are affected by the will. Thus, during a testamentary capacity evaluation, a forensic psychologist will investigate the extent to which the examinee demonstrates the above functional capacities as outlined by Probate Code 6100.5.

The Causal Component identifies the cause(s) of any deficits in functional abilities that exist. For instance, during a testamentary capacity evaluation, if an individual was unable to understand the nature of the testamentary act, the forensic psychologist might evaluate whether dementia, delirium, depression, psychosis, medication side effects, cognitive impairments, or other potential causes resulted in this impairment.

The Interactive Component determines the complexity of the act for which capacity is being assessed. Simple acts, such as executing an ordinary will, require less ability than more challenging tasks, such as executing a complex trust. An analysis of complexity requires the forensic psychologist to take the time to understand the specifics of the act that the examinee is being asked to do. For instance, the forensic psychologist would need to carefully read a trust to determine its complexity before providing an opinion regarding whether a testator demonstrated the capacity to execute it. Once the complexity of the act in question is determined, the forensic psychologist forms an opinion regarding the degree of congruity or incongruity between the examinee’s functional abilities and what is required of him, given the relative complexity of the act in question.

During the Conclusory Component, the forensic psychologist provides an opinion regarding whether there is a sufficient degree of congruity between the examinee’s relevant abilities and the complexity of the act in question to render the presence of capacity.

Finally, during the Remediative Component, the forensic psychologist provides an opinion of whether any cause(s) of incapacity can be remediated. For instance, if incapacity is caused by psychosis, treatment with antipsychotic medications may cause an individual to develop or regain capacity.

The Assessment of Testamentary Capacity, Contractual Capacity, and Undue Influence:

Although the legal standards for testamentary capacity vary by state, most U.S. states draw upon the criteria outlined in the landmark case Banks v. Goodfellow (1870). This case outlined criteria to consider during a testamentary capacity analysis, including the testator’s ability to know what a will is, know the natural objects of one’s bounty, know the nature and extent of one’s estate, and have a general plan for distribution.

In California, there are two primary legal standards that govern testamentary and contractual incapacity, PC 6100.5 (often referred to as the lower standard) and PC 812 (often referred to as the higher standard). Probate Code 6100.5 lists functional abilities to be considered, including the testator’s ability to understand the nature of the testamentary act, understand and recollect the nature of his property, remember and understand his relations and those who may be affected by the will, and divide the properties in a manner that does not result from delusions and hallucinations. Probate Code 812, which requires a higher degree of functional capacities, contemplates the testator’s ability to understand the rights, duties, and responsibilities affected by or created by the decision; understand the probable consequences to the decision-maker and persons affected by the decision; and understand risks, benefits, and reasonable alternatives.

Although undue influence is not formally a capacity, it is frequently assessed in conjunction with an analysis of testamentary capacity. Undue influence is a pattern of behavior by one or more persons with the goal of undermining the testator’s free will. Clinical features that may increase vulnerability to undue influence include isolation, dependency, and unexpected emotional changes. Demographic groups with an increased vulnerability to undue influence include white females over the age of 75, recent widows, and testators who are geographically isolated. Although numerous biological and psychiatric conditions may increase an individual’s vulnerability to undue influence, neurological disorders, mood disorders, and dependent personality disorder result in particular susceptibility. In California, undue influence is governed by Welfare and Institutions Code 1560.70, which identifies factors to be considered, including the vulnerability of the victim, the influencer’s apparent authority, the actions and tactics used by the influencer, and the equity of the results. Of these considerations, the forensic psychologist’s expertise is most suited to analyze the vulnerability of the victim and the influencer’s apparent authority.

The Assessment of the Capacity to Consent to Medical Treatment

American law protects the rights of individuals to decide for themselves whether to undergo medical treatment. Thus, it is critical that the capacity of an individual to consent to medical treatment is carefully assessed. Case laws establishes that informed consent for medical treatment requires three elements: disclosure of treatment-relevant information to patients by clinicians, the patient’s capacity to make a voluntary decision that is not the product of coercion or inducements, and the capacity to make medical decisions. The forensic psychologist expertise is relevant to this final criterion.

There is no specific legal standard that governs the capacity to consent to medical treatment. Nevertheless, legal reviews have identified four critical functional abilities. The first is the ability to communicate a choice of whether to engage or not engage in the treatment; second, the ability to understand relevant information about one’s disorders, treatments, and potential risks and benefits; third, the ability to understand the relevance of treatment information to one’s situation; and fourth, the ability to manipulate information rationally through a logical cost-benefit analysis of risks versus benefits. During a capacity to consent to medical treatment evaluation, a forensic psychologist may utilize Grisso’s model (described above) to assess capacity. Psychological tests developed for the assessment of the capacity to consent to medical treatment may additionally be utilized including the MacArthur Competence Assessment Tool for Treatment and the Hopemont Capacity Assessment Interview.

Dr. Teo Ernst is a Board-Certified Forensic Psychologist in the San Francisco Bay Area. He is an Assistant Clinical Professor in the UCSF Department of Psychiatry where he provides teaching and supervision on a voluntary basis. Dr. Ernst may be reached at (415) 913-8096 or .