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Capacity (Competence) and Incapacity


Charles Sabatino

, JD, American Bar Association

Reviewed/Revised May 2021 | Modified Sep 2022

Historically, “incapacity” was considered primarily a clinical finding, and “incompetency” was considered a legal finding. That distinction, at least in terminology, is no longer firmly recognized; most state laws now use “incapacity” rather than “incompetency,” although the terms are frequently used interchangeably. The more useful distinction in health care decision-making terminology now is between .

  • Clinical incapacity

  • Legal incapacity

People who have clinical and legal capacity with respect to health care have the right to make health care decisions, including refusal of medically necessary care, even if death may result from refusal. People who lack both capacities cannot make health care decisions. However, if a patient deemed by a physician to lack clinical capacity expresses a preference regarding a health care decision, the physician is not entitled to override that preference unless a court also deems the person lacks legal capacity to make that decision.

Clinical capacity

Clinical capacity to make health care decisions is the ability to understand the benefits and risks of the proposed health care, to understand possible alternatives, and to make and communicate a health care decision. Assessment of this capacity requires evaluation of the following:

  • Medical factors (eg, the patient's medical condition, sensory deficits, drug side effects, emotional and psychiatric issues)

  • Functional abilities (physical, cognitive, and psychologic)

  • Environmental factors (eg, stressful living conditions, availability of helpers, isolation, time of day variations cased by medication schedules or fatigue)

Appropriate health care practitioners determine this type of capacity when needed and document the determination process. Qualified health care practitioners, as defined by state laws, are legally empowered to make these determinations in almost every state under state advance directive laws. The courts become involved only when the determination itself or another aspect of the process is challenged by the patient or someone else.

Clinical capacity is specific to a particular health care decision and thus is limited to that decision. The level of clinical capacity needed to make a health care decision depends on the complexity of that decision. A patient with some decrease in capacity, even one with fairly severe cognitive deficits, may still have enough capacity to make simple health care decisions, such as whether to allow a rectal examination or placement of an IV. However, the same patient may lack the capacity to decide whether to participate in a clinical trial.

Pearls & Pitfalls

  • Clinical capacity is specific to a particular health care decision and thus is limited to that decision.

All feasible attempts should be made to involve the patient in decision making. Ignoring the decision of patients with capacity or accepting the decision of patients without capacity is unethical and risks civil liability. A patient's ability to carry out a decision is also important for physicians to assess. For example, a patient with a broken leg may be able to make the decision to return home but be incapable of self-care during convalescence. Providing the necessary support to carry out a decision becomes an important goal of care.

Capacity may be intermittent, variable, and affected by the environment. Patients who lack capacity due to intoxication, delirium, coma, severe depression, agitation, or other impairment may regain capacity when their impairment resolves. To obtain consent to treat a patient who lacks clinical capacity, health care practitioners must contact an agent or proxy designated in the patient’s durable power of attorney for health care or another legally authorized surrogate (Consent and Surrogate Decision Making Consent and Surrogate Decision Making When immediate decisions are medically required, the doctrine of presumed consent applies. In other circumstances, consent must be obtained. For most nonemergency medical decisions affecting... read more ). If urgent or emergency care is needed (eg, for an unconscious patient after an acute event) and there is no designated surrogate or the surrogate is unavailable, the doctrine of presumed consent applies: patients are presumed to consent to any necessary emergency treatment. The process of making emergency health care decisions for people who cannot make decisions for themselves is rarely litigated in court.

Legal capacity

Legal capacity (also called competency) is a legal status; it cannot be determined by health care practitioners. However, health care practitioners play an important role in the assessment process. In the US, people aged 18 or older are presumptively considered legally capable of making health care decisions for themselves. Emancipated minors are people below the age of majority (usually 18) who are also considered legally capable. The definition of this group varies by state but generally includes minors who are married, who are in the armed forces, or who have obtained a court decree of emancipation.

People remain legally capable until a judge with appropriate jurisdiction declares them legally incapacitated with respect to some or all areas of functioning. This declaration usually occurs through a guardianship or conservatorship procedure in the courts. The legal requirements for declaring legal incapacity vary by state. However, substantiation of some combination of the following is typically required:

  • A disabling condition (eg, intellectual disability, a mental disorder, dementia or other brain disorder, chronic use of drugs)

  • A lack of cognitive ability to receive and evaluate information or to make or communicate decisions

  • An inability to meet essential requirements of physical health, safety, or self-care without protective intervention

  • A finding that guardianship or conservatorship is the least restrictive alternative for protecting the person

If physicians question a person’s legal capacity, they may seek a court’s determination through guardianship or protective proceedings. Physicians may be asked to testify at or provide documentation for a hearing to determine legal capacity.

When the court declares a person legally incapacitated, it appoints a guardian or conservator to make legally binding decisions for the person, either in all matters or in a limited range of matters specified by the court. Courts can also make decisions about specific issues in dispute (eg, a particular treatment decision or the meaning of a particular instruction in the person’s living will).

Increasingly, the least restrictive alternative requirement for diminished legal capacity includes consideration of technological assistance and supported decision-making. Supported decision-making is an alternative to having a legal guardian and allows people with disabilities to keep their rights and their decision-making capacity with the help of trusted advisors, such as friends, family, or professionals, serving as supporters. Decision supports may involve informal help, technological assistance (eg, medical monitors that signal a need for action; mobile apps with assistive technology for people with disabilities), and formal agreements of support.

A small but growing number of states have recognized formal supported decision-making (SDM) agreements that can be used to enforce an individual’s right to obtain support from third parties. SDM agreements should define the elements of a supportive relationship and clearly recognize that the individual being supported remains the decision-maker. States are also increasingly recognizing supported decision-making in their guardianship statutes as a less restrictive alternative to guardianship.

More Information

The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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