Aid to capacity evaluation

Am Fam Physician. 2018;98(1):40-46

Author disclosure: No relevant financial affiliations.

Medical decision-making capacity is the ability of a patient to understand the benefits and risks of, and the alternatives to, a proposed treatment or intervention (including no treatment). Capacity is the basis of informed consent. Patients have medical decision-making capacity if they can demonstrate understanding of the situation, appreciation of the consequences of their decision, and reasoning in their thought process, and if they can communicate their wishes. Capacity is assessed intuitively at every medical encounter and is usually readily apparent. However, a more formal capacity evaluation should be considered if there is reason to question a patient's decision-making abilities. Such reasons include an acute change in mental status, refusal of a clearly beneficial recommended treatment, risk factors for impaired decision making, or readily agreeing to an invasive or risky procedure without adequately considering the risks and benefits. Any physician can evaluate capacity, and a structured approach is best. Several formal assessment tools are available to help with the capacity evaluation. Consultation with a psychiatrist may be helpful in some cases, but the final determination on capacity is made by the treating physician. If a patient is found not to have capacity, a surrogate decision maker should be identified and consulted. If the patient is unable to give consent and identifying a surrogate decision maker will result in a delay that might increase the risk of death or serious harm, physicians can provide emergency care without formal consent.

Informed consent involves providing patients with accurate and adequate information about the risks, benefits, and alternatives of a treatment in a manner that is free from coercion. It also requires that patients have medical decision-making capacity. Medical decision-making capacity has four key elements. Patients must be able to (1) demonstrate understanding of the benefits and risks of, and the alternatives to, a proposed treatment or intervention (including no treatment); (2) demonstrate appreciation of those benefits, risks, and alternatives; (3) show reasoning in making a decision; and (4) communicate their choice. 1 , 2

Capacity differs from competence. Although the terms are often used interchangeably, competence is a legal term that is determined by the court system, whereas capacity is a medical term that is determined by the treating physician. According to their strict definitions, lack of competence refers to global decision-making impairment (e.g., finances, property, wills), whereas lack of capacity refers to the inability to make decisions about proposed medical treatments and other aspects of care. Capacity can vary with circumstance; for example, a patient can have the capacity to make small, straightforward decisions such as consenting to take a new medication, but may lack the capacity to consent to a high-risk abdominal surgery. 3

Generally, a patient's capacity is readily apparent, and physicians intuitively assess capacity at every medical visit. Because the four elements of capacity (understanding, appreciation, reasoning, and communication) are built into everyday dialogue and interactions, it can be assumed that patients have the capacity to make medical decisions if their conversation demonstrates basic logic. However, a patient's capacity may come into question if the dialogue does not proceed in a logical fashion, if there are abrupt changes in the patient's mental status, or if the patient refuses an obviously beneficial treatment, has a risk factor for impaired decision making (Table 1 3 – 5 ), or readily agrees to an invasive or risky procedure without discussing or considering the risks and benefits. 3 If the physician has doubts about a patient's ability to make a decision, a more formal evaluation of capacity should be undertaken. The results can either give the physician confidence to adhere to the patient's wishes or, if a lack of capacity is indicated, to take steps to restrict the patient's autonomy in order to prevent unintended and irreparable harm.