Medical Decision-Making Capacity of Patients With Dementia

Psychiatric TimesPsychiatric Times Vol 26 No 12
Volume 26
Issue 12

The United States Census Bureau projects that by 2010 nearly 13% of the US population will be over the age of 65. The elderly are one of the most rapidly growing segments of the US population and are expected to account for more than 20% of the total population by 2050.1 In 2001, the prevalence of dementia in North America was 6.4%. A 49% increase in the number of people with dementia is expected by 2020, and a 172% increase by 2040.2 Patients with dementia may lack the capacity to consent to treatment. The need to evaluate capacity to consent to treatment will therefore increase as the aging population grows.

The United States Census Bureau projects that by 2010 nearly 13% of the US population will be over the age of 65. The elderly are one of the most rapidly growing segments of the US population and are expected to account for more than 20% of the total population by 2050.1 In 2001, the prevalence of dementia in North America was 6.4%. A 49% increase in the number of people with dementia is expected by 2020, and a 172% increase by 2040.2 Patients with dementia may lack the capacity to consent to treatment. The need to evaluate capacity to consent to treatment will therefore increase as the aging population grows.


Mrs E, who is 80 years old, lives in the community with the help of a 24-hour-a-day home health aide. She is forgetful and requires assistance with many activities of daily living.

Mrs E is brought for evaluation because she has been crying more frequently. She remains in bed for most of the day, does not engage in activities she used to enjoy, and is sleeping and eating less than usual. The doctor recommends a trial of an antidepressant, which Mrs E refuses. She states, “I’m 80 years old and I’m not about to start taking medications now. That would kill me!”

How can her doctor determine whether she has the capacity to refuse treatment for depression?

In 1990, Congress passed the Patient Self-Determination Act (PSDA). The PSDA requires many Medicare and Medicaid providers-including hospitals, nursing homes, hospices, and HMOs-to give patients information about their rights, including their right to accept or refuse medical or surgical treatment. The law clearly intends that residents of nursing homes retain their right to accept or refuse treatment. Our society places a high value on an individual’s autonomy by generally allowing people to make decisions for themselves, even if the decisions confer the risk of substantial harm (for example, bungee jumping).

Many of the rights that we take for granted derive from the legal concept of a “liberty interest” that protects individuals from unwanted intrusions on their person. Some people question whether a person with dementia should retain this sense of self and autonomy or whether family members should make medical decisions for him or her. During the past 10 years, there has been an increased recognition that persons with dementia retain a sense of self, complete with preferences, despite cognitive loss.3

There are many safeguards in place to protect a person’s independence. In particular, the doctrine of informed consent for medical treatment has been designed to preserve a patient’s autonomy by limiting the doctor from touching, operat-ing on, medicating, or exerting control without the patient’s expressed agreement. This doctrine applies to all persons, including patients with dementia.

How much information is too much information?

Informed consent in a medical context consists of 3 elements (Table 1): disclosure of information, voluntary acceptance of treatment, and mental capacity. In this article, we discuss whether patients with dementia can offer informed consent for treatment and how physicians can negotiate such consent.

Let us first examine the primary element of informed consent: information. How much and what kind of information should the physician share? Does it help the patient to know that 1 in 1000 patients experience a particularly serious adverse effect? What if 1 in 100 patients has a minor reaction: would that change whether the patient should be told about the potential adverse outcome?

Two landmark court cases have clarified how much information should be provided. First, the court in Natanson v Kline established that the clinician should provide information that the “reasonable medical practitioner” would customarily disclose to a patient.4 Later, in Canterbury v Spence, a court shifted its position and ruled that the doctor should provide information that a “reasonable person” would want to know in order to decide whether to accept or refuse the proposed treatment.5 This shift from what the reasonable practitioner would discuss to what the reasonable person would want to know directed the clinician to consider knowledge of the patient’s specific circumstances and mental state.

It is acceptable for physicians to exercise therapeutic privilege and withhold certain information at their discretion if they deem that the information would pose a serious psychological threat by cognitively overwhelming the patient or causing panic.

Consent must be voluntary

The second element of medical informed consent is that the patient’s consent be given voluntarily. This implies that the patient’s decision is free from coercion. Coercion can be obvious-as in the case of an institutionalized patient who is told that she will have to continue wearing hospital gowns until she takes her medication-or it can be subtler-as in the case of a physician whose policy is to complete disability paperwork only for patients who agree to the proffered treatment. In both cases, coercion interferes with the patient’s ability to freely give informed consent.6 When examining patients with cognitive deficits, it is important to recognize that the more emotionally dependent and cognitively impaired they are, the more susceptible they are to even subtle coercion.7

Capacity to consent to treatment

The third essential element in the informed consent process-the capacity to consent to treatment-is the most crucial aspect for the clinician to consider (Table 2). To be considered capable of consenting or refusing treatment, the patient must be able to:

• Communicate a clear choice without vacillating significantly.

• Demonstrate a factual understanding of the medical issues at hand, including the risks and benefits of the treatment and any reasonable alternatives.

• Show comprehension of the situation as it applies to him and the consequences of his decisions. This implies that the patient has psychological insight into his illness and need for treatment.

• Display a rational manipulation of the information presented with a coherent and logical thought process in analyzing the various courses of action. This element examines the process and not the content of the person’s thoughts.8

People are allowed to make decisions that are contrary to their physician’s best advice, as long as all 4 of these criteria are met. For example, if a person with depression and mild dementia takes an acetaminophen overdose in a suicide attempt, he can be retained in the hospital on an emergency basis because he poses a threat to himself. However, he may or may not have the capacity to refuse medical treatment regardless of his involuntary status. Establishing a patient’s capacity to consent to treatment protects the patient’s presumed autonomy while protecting those whose cognitive impairment precludes the ability for meaningful and lawful consent.

Dementia, delirium, depression, psychosis, and drug intoxication, along with other psychiatric syndromes, can affect a person’s capacity to provide consent for treatment. Conversely, having any one of these conditions does not, per se, indicate a lack of capacity to consent to treatment.

Each person must be evaluated to determine whether he has the capacity to consent to the specific treatment at a particular time in the course of his illness. Patients with severe and chronic dementia, those who have a Mini-Mental State Examination (MMSE)9 score of less than 16, have a high likelihood of being unable to consent to treatment. One study of 98 patients with Alzheimer-type dementia found that only 11% of the patients with MMSE scores of less than 16 retained decision-making capacity.10

Other studies have found that patients who have mild cognitive impairment (ie, those with episodic memory impairment who do not meet criteria for dementia) are more likely than those without cognitive impairment to have impaired decision-making capacity. Mild cognitive impairment can erode the ability to remem-ber, understand, and apply medical information that has been presented, thereby impairing decision-making capacity while leaving the person relatively intact during activities of daily living.11

Other investigators have noted that patients with mild cognitive impairment frequently display deficits in executive functioning, specifically in areas of abstract thinking and cognitive flexibility. These deficits also degrade decision-making capacity, especially understanding the conse-quences of a treatment choice.12,13

The Clock-Drawing Test, which consists of asking the patient to “please draw a clock, fill in the numbers and set the time to 10 past 11,” is a useful screening tool because it tests a number of cognitive skills: comprehension, planning, abstract thinking, and executive function.14 Cognitive screening tests may help identify patients who need a more extensive evaluation of their capacity to consent to treatment, but they cannot be relied on to determine the ability to consent.

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.

Decision-making capacity

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


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.




US Census Bureau. Percent Distribution of the Projected Population by Selected Age-Groups and Sex for the United States: 2010 to 2050.

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Marson DC, Chatterjee A, Ingram KK, Harrell LE. Toward a neurologic model of competency: cognitive predictors of capacity to consent in Alzheimer’s disease using three different legal standards.




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Feinberg LF, Whitlatch CJ. Are persons with cognitive impairment able to state consistent choices?




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Okonkwo OC, Griffith HR, Copeland JN, et al. Medical decision-making capacity in mild cognitive impairment: a 3-year longitudinal study.



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