Amid an aging, growing population, family physicians will need to learn how to navigate the intricate landscape of determining patient mental capacity in legal disputes.1 This is shaped by an unprecedented transfer of wealth from an older population with cognitive and mental health challenges to a younger generation with complex families under great economic strain.2 This scenario will inevitably result in more legal challenges to wills, powers of attorney, gifts, and other estate-related acts. Accordingly, more requests will come from lawyers for physician opinion on patient mental capacity. This task is related to, yet distinct from, the universal responsibility of all physicians to assess, when necessary, their patients’ capacity to consent to treatment.

Herein, we outline 6 key considerations for family physicians who are asked to address questions of mental capacity that fall under the purview of the law, such as estate-related decisions, but for which the legal determination often benefits from medical input.

Mental capacity is subsumed by 2 fundamental components. The first component of mental capacity involves understanding relevant facts. The second is the appreciation of reasonably foreseeable consequences of making or not making a decision. Patients must freely and consistently communicate their decisions and their rationales. Consideration of these components is especially important when there is a substantial departure from previous patterns of decision making, for example, in the execution of wills or in the designation of powers of attorney.

Capacities are specific to the decision or task, situation, and time. Capacity questions addressed to physicians from lawyers often result in brief and sweeping opinion letters. However, physicians must avoid making general or overarching capacity statements such as “this person has the capacity to make legal and financial decisions.” Capacities cannot be globally assessed. An individual might be capable in some spheres and incapable in others. Situation-specific factors, including complexity and the conflictual nature of the individual’s personal environment, affect the capacity threshold. The more complex and contentious the situation, the greater the need for cognitive ability to sort out competing claims and meet the threshold for having the requisite capacity. The question a physician must always ask is “does this person have the capacity to make a specific decision or perform a specific task in a particular circumstance or environment at a defined point in time?”

Capacity cannot be determined by a cognitive test score or diagnosis alone. A formal diagnosis, even of dementia or another cognitive disorder, does not equate to incapacity. Similarly, scores on common formal cognitive screening tests, such as the Montreal Cognitive Assessment,3 are not a proxy for capacity. They solely provide a snapshot measure of one’s overall level of cognitive functioning, which can also be used to track the trajectory of cognition over time. Clinicians must be mindful that social behaviour can mask cognitive impairment if not probed further. It is very easy to miss cognitive impairment if one does not formally test cognition or make inquiries of informants. Ultimately, capacity rests on whether an individual can meet specific legal criteria, irrespective of that individual’s diagnosis or test performance.

However, a case has been made for the use of structured decision-making tools, such as the Contemporaneous Assessment Instrument,4 to aid in assessments of capacity. This tool has prima facie validity but has not yet been replicated in randomized trials. Assessment of capacity remains an individual clinical determination.

There is a distinction between a clinical opinion and a legal test for a specific capacity. Aside from the capacity to consent to treatment (including medical assistance in dying), most capacities are defined by legal criteria and are ultimately a judicial determination. Yet, mental capacity involves cognition and executive brain functions, which can be affected by psychiatric symptoms, such as delusions, and syndromes, such as dementia and delirium.5 Thus, the assessment of capacity invites medicolegal collaboration where input from clinicians or experts is sought in the form of an “opinion.” However, that input is not a legal opinion and the court is often asked to evaluate differing clinical opinions.

Alternatively, physicians might simply provide the court with a description of the nature and severity of any cognitive, neurologic, or psychiatric disorders that might impact the legal test for a specific capacity. If a lawyer does request a clinical opinion from a physician, the lawyer should also provide guidance as to the legal test that applies. That test might involve case law, as in the capacity to make a will, to gift, or to marry; or regulatory statutes, which subsume capacity to manage property or personal care and to revoke or grant powers of attorney. These legal statutes might differ by local jurisdiction, and physicians should be familiar with their provincial guidelines.

When considering questions of undue influence, it is only a patient’s vulnerability to influence that should be determined by a physician.2 Often paired with a challenge to mental capacity is the allegation of undue influence, a legal concept that involves the subversion of one person’s will by another.6 Undue influence is a form of financial abuse when exerted on vulnerable individuals. Historically, undue influence was associated with coercion, but subversion of will is a more apt concept. It is now well established that it would not necessarily take coercion or severe pressure to cross the theoretical threshold of undue influence over an individual who has increased vulnerability in the form of cognitive impairment or emotional instability, as determined by a judge. The physician is tasked primarily with considering a patient’s vulnerability to influence, not with attempting to ascertain whether influence is or is not being exerted. This distinction is critical, as determining the presence of influence remains within the purview of the court—the trier of fact—not the physician.

Consider clinical red flags in all questions of capacity. The presumption of capacity is spent when there are suspicious circumstances or red flags. The following factors should raise concern about capacity: substantial deviation from a previous pattern of behaviour or expressed wishes, especially in older individuals, where the prevalence of cognitive impairment is highest (age alone should not be equated with incapacity); deathbed decisions7; an established concurrent diagnosis of a psychiatric or cognitive disorder8; and concurrent polypharmacy and medical frailty.

Physicians receive insufficient training or education in mental capacity assessment. Given increasing challenges to mental capacity, it is important to enhance medical education on capacity assessment at all levels.

At the undergraduate level, incorporating clinical skills training and case-based learning focused on common capacities will provide students with valuable opportunities to engage in real-time capacity assessments and formulate clinical opinions. At the postgraduate level, relevant disciplines should be targeted, such as family and community medicine, psychiatry, neurology, and geriatric medicine, and capacity assessment should be incorporated in competency-based education.9 The issues surrounding capacity highlight the importance of a nuanced understanding and robust collaboration between medical and legal professionals. Capacities are decision and situation specific, and overarching, generalized statements about capacity are not helpful. Family physicians need to understand and address the essential elements of mental capacity in any opinion they render for legal purposes to ensure that their assessments are both medically sound and legally defensible.

An understanding of capacity is necessary to ensure that the human right to dignity and safeguards against financial abuse are respected. This understanding supports the balance between maintaining the autonomy of those making capable decisions and protecting those who are incapable.9

Competing interests

None declared

The opinions expressed in this article are those of the authors. Publication does not imply endorsement by the College of Family Physicians of Canada.

This article has been peer reviewed.

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