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The Continuum of Consent

By Currents Editor posted 06-03-2020 13:53


By Jamie Nicole LaBuzetta, MD, MSc, MPhil

UC San Diego, Dept of Neurosciences, Division of Neurocritical Care

In a prior Currents article, I discussed that in order to obtain informed consent or refusal for medical care, a clinician must ensure decision-making capacity; disclose risks/benefits of a procedure or treatment and its alternatives; evaluate comprehension of those risks and benefits; and obtain voluntary agreement. 

Because informed consent and informed refusal require decision-making capacity, a capacity assessment — even if informal and unstructured — is a necessary precursor to consenting a patient for diagnostic tests or treatment.

Capacity has four elements:1

  1. Understanding the information delivered to them about proposed tests or treatment
  2. Appreciation of how to apply this information in their specific situation
  3. Reasoning (to make a choice)
  4. Communication of a choice

Clues that a patient may be lacking capacity include decisions that are irrational or inconsistent with previously expressed goals.2 

Sometimes, a patient clearly does not have capacity. However, assessing capacity can be complicated.  In my experience, some misunderstandings regarding capacity exist even amongst experienced clinicians. These misunderstandings include:

  1. Capacity (and consentability) are static.
    All too often, I see patients labeled as “does not have capacity” with no plan to readdress. However, capacity is dynamic.  An individual who lacks capacity at time point No. 1 because of a reversible condition (eg, delirium, metabolic disturbance, intoxication) may be consentable once the condition is appropriately treated or controlled. The corollary is that a patient who had capacity to make a medical decision may lose capacity because of a change in mental status, and during this time, would be unable to consent for him or herself. An assessment of capacity should be made at every patient encounter.
  2. Capacity is binary — all or none.
    Capacity is task specific. This means that a capacity assessment must be made for each medical decision; does the patient have capacity to make a specific decision? A patient may have the capacity for one type of medical decision but not another.
  3. Equating “alert and oriented” with having capacity
    I have witnessed many a trainee attempt to consent a patient who lacks decision-making capacity, and justifying that attempt by saying that the patient was alert and oriented. On the other hand, I have also witnessed physicians attempting to consent a surrogate for a patient who is capable of making certain decisions themselves.  Indeed, a patient may only be oriented to himself and still evidence the necessary components of a capacity assessment and consentability for specific decisions.  Equally, a patient may be fully oriented and be unable to understand (or communicate) the information presented to them, thus lacking capacity to make some medical decisions.
  4. A formal psychiatry consult is required to assess capacity.
    Informal, unstructured assessments of capacity are often difficult, with low inter-rater reliability.3 There certainly are instruments designed to evaluate medical decision-making (eg, Aid to Capacity Evaluation, MacArthur Competence Assessment Tool for Treatment), but there is no gold standard.  A recent review notes that the inclusion of an MMSE or MOCA can be helpful in guiding the capacity assessment, but are not synonymous with the capacity assessment.3 The assessment can be performed by any clinician who will obtain informed consent and must be guided by the consideration of the four components (understanding, appreciation, reasoning, communication), although institutional policies may require that formal psychiatric or neuropsychological assessments be done in cases where capacity is questionable.


There are temporal and situational aspects of capacity, as well as an interrelationship between consentability and capacity. For this reason, I like to think of consentability as a continuum from definitively lacking capacity (and therefore not consentable) to definitively capable of consenting (see Figure 1). 

Figure 1: Capacity is dynamic. As such, a patient may not have capacity in one instance, but may have capacity at another time point.

It can be tempting to assume that patients who refuse beneficial treatment lack decision-making capacity, but refusal of medical care denotes neither incompetence nor lack of capacity.  Capacity influences the right to determine what happens to one’s own body, even if refusal of medical care may result in injury or death. In the absence of healthcare consent capacity, the principle of autonomy transitions to a surrogate decision-maker. In circumstances of refusal of medical care, the physician has a duty to inform the decision-maker about the potential risks of their refusal. 


Regardless of whether a patient is incapacitated, though, ongoing communication with the patient should be encouraged.  Lack of capacity is not an appropriate reason to exclude them from the information process, and when excluded, patients may find this situation frightening without a sense of what is happening to them and their person. For instance, if a patient lacks capacity, and a surrogate decision-maker consents to arterial catheterization, the patient’s assent (or at least lack of active dissent) for that procedure is still desired; thus, sharing information with the patient about clinical activities is to everyone’s benefit.



  1. Grisso T, Appelbaum PS. Assessing competence to consent to treatment : a guide for physicians and other health professionals. New York: Oxford University Press; 1998.
  2. Marco CA, Brenner JM, Kraus CK, McGrath NA, Derse AR, Committee AE. Refusal of Emergency Medical Treatment: Case Studies and Ethical Foundations. Ann Emerg Med 2017;70:696-703.
  3. Palmer BW, Harmell AL. Assessment of Healthcare Decision-making Capacity. Arch Clin Neuropsychol 2016;31:530-40.


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