Many medical practitioners rely on a sliding scale approach to setting thresholds for accepting a patient’s treatment decisions. In the case of a patient who wishes to consent to a low-risk, high-benefit intervention, a relatively lower standard of capacity is used. Requiring only minimal capacity protects the patient’s autonomy as well as his physical well-being. Patients are generally allowed to consent to low-risk, high-benefit treatment, such as an antidepressant, as long they can communicate a choice. Many patients with dementia fall into this category. However, receptive aphasia and severe expressive communication deficits in advanced Alzheimer-type dementia could prevent the ability to communicate a choice, the lowest standard for determining capacity.
Feinberg and Whitlatch15 found that patients with mild to moderate cognitive impairment were able to state consistent choices regarding decisions that affected everyday life. They also found that patients with dementia and their caregivers appreciated that the patient’s choices and preferences were elicited and attended to.
Capacity is typically only called into question when a patient refuses the proposed treatment. Patients who oppose treatment are routinely held to higher standards of capacity because they run the risk of physical harm, which goes against the right to treatment and the ethical principle of beneficence.16
One study showed that physician reports were more likely to find that a patient had the capacity to consent to treatment than were reports from family members or results of structured tests.17 This finding probably accounts for physicians’ use of a sliding scale approach to determine capacity and their belief that a person should be allowed to consent to a low-risk, high-benefit treatment, even when the patient lacks full ability to reason and appreciate. Family members were more likely to deem the patient unable to make medical treatment decisions if, for example, he required assistance with daily activities such as shopping and cooking. Such criteria do not reflect a medical or legal definition of capacity.17
If a patient is found to lack capacity to make a medical decision, a proxy decision maker must be appointed by the court. It is especially important to have a proxy appointed if the treatment carries both high risks and high benefits. In such a situation, it may not be clear whether the patient should have the treatment. The proxy must take into account the patient’s previously expressed wishes, long-held beliefs, and idiosyncratic preferences when deciding to accept or refuse the proposed treatment.18 If there is no clearly designated health care proxy, the patient may have a guardian appointed by the court, who can make medical decisions on the patient’s behalf.
In assessing a patient’s decision-making capacity, the physician must first establish that the patient has been provided with all the information about his condition and the proposed intervention that would be needed to make an informed decision. Verbal and written information can sometimes be helpful to patients.
The next step is to clinically assess the patient’s choice about whether to accept the proposed treatment, his understanding of the relevant information, understanding of his situation, and ability to rationally manipulate the information. Collateral information from family, friends, and past treatment providers can also be useful. The clinician should be satisfied that the patient is making a voluntary decision without being coerced.19
When it is not clear whether the patient has the capacity to consent, or when future litigation is likely, structured assessment instruments, such as the MacArthur Competence Assessment Tool, can be used.20,21 However, the clinical interview remains the gold standard in assessing patient’s capacity.22,23 (Please refer to Eth and Leong19 for a more in-depth discussion of obtaining voluntary informed consent.)
Capacity is not static
Decision-making capacity must be evaluated for each medical decision, because it is neither static nor broad-based. A patient may lack the capacity at one time and later have that capacity restored. Some common factors that can temporarily and reversibly cause a person to lack medical decision-making capacity include delirium, depression, polypharmacy, nonadherence to medication, or an acute medical illness or infection. Many patients with mild to moderate dementia have fluctuations in their levels of capacity, depending on the familiarity of the setting, time of day, and medications taken.
If a patient is found to lack capacity to consent to treatment, efforts should be made to improve his mental status and capacity, unless a decision must be made immediately. The use of simple language when giving information, presenting information repeatedly over time, and providing corrective feedback to a patient’s misunderstandings can be helpful in achieving sufficient capacity.24 Nevertheless, in some cases, capacity cannot be restored. Numerous studies have shown that the cognitive declines associated with mild cognitive impairment and dementia are progressive and are associated with a similar progression of decline in medical decision-making capacity.25,26
CASE VIGNETTE, cont’d
The psychiatrist assesses Mrs E and builds a treatment alliance with her over the first 2 appointments. The psychiatrist educates Mrs E about the signs and symptoms of depression and helps her understand that she is experiencing a mood disorder. Mrs E gains insight into her condition and an understanding of how proposed medications may help her. Mrs E agrees to a trial of an antidepressant medication and her decision is accepted as reflecting voluntary informed consent as legal authorization for the treatment.
Many patients with mild cognitive impairment or mild to moderate dementia retain the capacity to consent to medical treatment. When a physician is faced with evaluating whether a patient has the capacity to refuse medical treatment, clinical evaluation of the patient’s choice, understanding, appreciation, and reasoning remain the gold standard for determining capacity. Tests of cognitive function or formal tests of decision-making capacity do not replace the clinical examination, because such tests fail to recognize the sliding scale nature of capacity when applied to clinical decision making for a particular patient.