Competency and Capacity

Article Author:
Christopher Libby
Article Editor:
Gary Gillette
11/5/2018 4:48:35 PM
PubMed Link:
Competency and Capacity


It is important healthcare providers ensure that every treatment or refusal of treatment is done with informed consent. One of the foundational principles of medical ethics is a patient’s autonomy to make personal medical decisions. However, there are times when a patient may not be able to make those decisions for themselves. This is where another principle of medical ethics, beneficence, must be utilized. When a patient makes a decision that may not be in their best interest, according to the provider, it may prompt the provider to weigh patient autonomy against beneficence.

By law physicians and non-physician providers are required to obtain informed consent before initiating any medical treatment for a patient. According to the American Medical Association’s Code of Medical Ethics, to achieve informed consent, the patient must meet the following criteria:

Assess the patient’s ability to understand relevant medical information and the implications of treatment alternatives and to make an independent, voluntary decision

Present relevant information accurately and sensitively, in keeping with the patient’s preferences for receiving medical information. The physician should include information about:

  • The diagnosis (when known)
  • The nature and purpose of recommended interventions
  • The burdens, risks, and expected benefits of all options, including forgoing treatment

Document the informed consent conversation and the patient’s (or surrogate’s) decision in the medical record in some manner. When the patient/surrogate has provided specific written consent, the consent form should be included in the record.

However, there are times when a patient’s ability to meet criteria A are not as easy to understand. When a patient cannot make an informed, independent, and voluntary medical decision, an alternative decision maker, must be sought who is acting in the best interests of the patient. Thus, it is critical for providers to be able to determine whether the patient can make a medical decision.

Issues of Concern

When determining the ability of a patient to make a medical decision, it is common in medical settings to hear the terms competence and capacity used interchangeably.[1]. However, it is critical to understand that these terms have separate but overlapping meanings.  


Competency is a legal term referring to an individual’s mental ability and cognitive abilities to execute a legal act. The determination is strictly a judicial determination based on several inputs from witnesses which may or may not include physicians and/or psychiatrists. It includes both the mental capacity to make medical decisions as well as the functional capacity of the individual to communicate those decisions or perform activities of daily living. If a person is determined to legally not have the competency for medical decisions, they will be assigned a guardian by the court. These court cases can be quite a labor intensive as it denies a person their rights of autonomy.[2]


In contrast to the legal term of competency, physicians determine the capacity for a patient to make a medical decision. This decision is dependent on the magnitude of the decision and the ability of the patient to truly understand the gravity of the decision.

For a patient to demonstrate their capacity to make medical decisions, they must understand the following about the decision:

  • Understand relevant information about proposed diagnostic tests or treatment
  • Appreciate their situation
  • Use reason to make decisions
  • Communicate their choice

It is important to note that a patient’s capacity to make a decision is both situational and temporal. This means that a capacity assessment must be made for each medical decision as a patient may have the capacity for one type of medical decision, but not another. A change in a patient’s mental status can drastically affect their capacity to make a particular medical decision.

Furthermore, depending on the gravity of the decision, a patient may have the capacity to refuse to give a urine sample but not have the capacity to refuse further evaluation. This is a grey area as the gravity of the decision may vary depending on the values of the provider and the patient. In general, the greater the importance of the decision, the greater the capacity the patient must demonstrate. (Figure 1)

Clinical Significance

In the absence of a situation in which a patient is incapacitated requiring implied consent for life-saving medical treatment, the ability of the patient to make an informed decision is critical to clinician-patient interactions. Challenges arise when clinicians are unsure of a patient’s capacity to make a decision and how to test capacity. This results in a large, practical variation in how clinicians assess capacity and obtain informed consent.[3]

When to Assess

Without a reason to question otherwise, it is assumed that patients can make informed decisions. However, there are many situations in which a patient may have either permanent or transient cognitive deficits warranting further evaluation of their capacity to make an informed decision.

Example of Conditions Associated with Cognitive Impairment:

  • Major depressive episode[4]
  • Schizophrenia[5]
  • Delirium[6]
  • Dementia[6]
  • Developmental delay
  • Substance abuse
  • Traumatic brain injury

Furthermore, it may be appropriate to assess capacity when decisions by a patient are deemed high risk and will likely result in otherwise preventable harm.

Examples of High-Risk Decisions

  • Refusal of low risk, high reward procedures such as percutaneous intervention for STEMI
  • End-of-life decisions[7]
  • Refusal of antibiotics in critical illness
  • Refusal of insulin in insulin dependent diabetes mellitus

Who Can Assess

When assessing capacity to make a medical decision, a clinician must ensure they adequately assess the patient's mental status and understanding of the decision. Psychiatrists are often called upon in courts to assess capacity when determining legal competency or when a guardian is being appointed. However, in the clinical setting, any clinician can assess capacity and should assess capacity as part of informed decision making. When there is a question of capacity, psychiatrists may be able to assist by providing an additional evaluation, but this should be done after initial evaluation by the clinician discussion an intervention.[8]

Other Issues


Patient Refuses Assessment

Patients have the right to refuse both treatments and participation in evaluations. This may be due to a lack of trust in the provider or due to other personal factors. The best approach to these situations is to build the clinician-patient relationship based on trust and respect. However, there are times when this is not possible. In those situations, the clinician must inform the patient that the assessment will still need to be made based on all the available information at the time. If the decision can be postponed and is not necessary to be made immediately, it is preferred to delay the decision until a more thorough evaluation can be made.

Family and Friends Disagree with Assessment

Studies have shown that family members of a patient's close family and friends often underestimate a patient's level of cognitive impairment. Even clinicians can miss impairment in patients without using formalized tools.[9] When those close to a patient disagree with a clinicians determination of capacity, it may be helpful to explain how the patient is impaired using formalized capacity assessment tools. Based on family values, cultural preferences, and religious beliefs the clinician may have to tailor their discussions with the patient and the family to achieve optimal patient care.

Patient Has Capacity and Refuses Life Saving Treatment

Patients with the capacity to make medical decisions can and do refuse life-saving medical interventions for a variety of reasons. It is common to encounter patients who belong to religions such as the Jehova's witnesses who refuse blood products. This can be very frustrating to some clinicians, but the ability to refuse treatments is based on the fundamental ethical principle of patient autonomy. When faced with patients that refuse life-altering interventions, clinicians must be sure to discuss all aspects of the decision with the patient as well as alternative options. Formal capacity assessment tools can be helpful to document discussions and refusal of care. Ultimately, clinicians must respect a patient's right to make their own decisions even when the clinician disagrees. 


Minors may have the capacity to make medical decisions based on age and state law. Some decisions are protected such as those related to contraception, STIs, and for emancipated minors while others will require parental consent. It is recommended that each clinician review their relevant state laws.

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      Contributed by Christopher Libby MD, MPH