Physicians and other healthcare providers must make a determination about a patient’s decisional capacity whenever they ask a patient to choose a form of treatment or care. Much of the time, the determination of capacity is implicit, in that the vast majority of individuals are fully competent to make decisions about their health care, and the medical team must respect whatever choices the person makes.
However, in persons with dementia and other significant cognitive disorders, decisional capacity must be explicitly determined in every situation. An individual with dementia may have the capacity to make certain decisions which are not very complex or abstract, but not have the capacity to make more difficult decisions; that is to say, decisional capacity is fluid, and dependent on the nature of the decision which needs to be made. For example, an individual with significant dementia may be able to decide whether he would prefer soup or a sandwich for lunch but may not have the capacity to make decisions about the nature of medical and other care he wishes to receive.
In general, persons with more severe cognitive impairment are more likely to lack decisional ability, although there is no exact correlation between any measure of cognitive impairment and the presence or absence of decisional capacity. Two individuals with the same score on a cognitive test may differ as to whether or not they have capacity; thus, an individual determination must be made in each case. It is also important to recognize that capacity may vary in a given person depending on the circumstances. Someone who is extremely fatigued, or stressed, or acutely medically ill (even with a relatively trivial illness, such as a urinary tract infection, for example, may lack capacity. However, if the same individual is well rested, not stressed, and no longer acutely ill, he or she may demonstrate full decisional capacity. Therefore, whenever possible, assessment of decisional capacity should be done when an individual appears to be at his or her baseline.
In order to determine whether or not someone has capacity for a given decision, the physician or other healthcare provider must make a determination about four capabilities (Appelbaum, 2007):
- Does the person understand the choices which are being presented, along with the potential risks and benefits of each choice? Does he or she comprehend what the physician is saying, and can the person repeat it back to the physician in his or her own words? If he or she is not able to repeat the choices, can he or she recognize them when restated by the physician? Significant short-term memory impairment can make this task very difficult, if not impossible.
- Does the person appreciate his or her present condition? In other words, does the person have any insight into his or her difficulties? Individuals who lack insight into their condition are generally not felt to possess capacity to make decisions about their care.
- Is the person able to clearly and consistently state his or her choice for care from among the options which have been presented? Frequent or inconsistent changes in the choice made, or an inability to select from among the options offered, may indicate a lack of decisional capacity.
- Is the person able to communicate his or her reason(s) for the choice made? In other words, can the person explain why he or she has chosen the particular option(s) offered? Of course, this is not a matter of whether or not the physician agrees with the choice made, but whether or not there are rational explanations given for the choice, whatever it may be.
All four of these capabilities must be present for an individual to possess decisional capacity.
Put another way, a person does not possess decisional capacity if:
- He or she is unable to understand the information which is relevant to the decision.
- He or she cannot retain information for the time required to make the decision.
- He or she is unable able to appreciate the relevance of the information or to utilize the information appropriately to make the decision.
- The person is unable to clearly and reliably communicate his or her decision (Pennington et al., 2018)
There are a number of assessment tools clinicians may use to assist them in determining decisional capacity in a variety of clinical situations (Dunn et al, 2006; Lim and Marin, 2011).
References:
Appelbaum PS. Assessment of Patients' Competence to Consent to Treatment. The New England Journal of Medicine. 2007;357:1834-1840.
Dunn LB, Nowrangi MA, Palmer BW, Jeste DV, Saks ER. Assessing Decisional Capacity for Clinical Research or Treatment: A Review of Instruments. American Journal of Psychiatry. 2006;163:1323-1334.
Lim T, Marin DB. The Assessment of Decisional Capacity. Neurologic Clinics. 2011;29:115-126.
Pennington C, Davey K, Ter Meulen R, Coulthard E, Kehoe PG. Tools for testing decision-making capacity in dementia. Age and ageing. 2018;47:778-784.