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Appendix 2: Assessing decisional capacity

When assessing a patient’s decisional capacity, you should be seeking to answer three questions:

Question 1– Does the patient have a mental disorder?

Bear in mind that a mental disorder may be permanent, temporary or fluctuating. If it is temporary, and the decision is not urgent, then defer it until the patient has regained capacity.

Look for and treat any underlying physical conditions that might be causing temporary incapacity (eg, an elderly patient with a urinary tract infection is confused, but regains her lucidity once the infection has been treated). If the patient’s mental capacity fluctuates, try to time your assessment to coincide with his most lucid periods. The patient’s carers will probably be able to help you identify the best time of day for such a discussion.

Question 2 – Is the patient able to make the decision in hand?

Assuming you have reasonable grounds for believing that the patient has a mental disorder, your next task is to decide whether, on the balance of probabilities, it has rendered the patient incapable of making a decision. While a checklist might be useful for guiding you through the process and for recording your main findings as you go, the assessment itself is not a tick-box exercise. It is a dialogue in which you and the patient impart information to each other and on which you base your judgment of the patient’s understanding and thought processes.

Unless the patient is limited to yes/no answers (eg, blinking), you should try to frame as many of your questions as you can in an open-ended format. Bear in mind that you are not judging the patient’s eventual decision; you are assessing the thought processes that led to the decision. In other words, it is not what patients decide that determines their capacity, but how they reached the decision. If the decision-making process is consistent with the patient’s beliefs and values and is logically coherent, the patient is demonstrating mental capacity, even if the decision may seem unwise.

You should make all reasonable efforts to help the patient make a decision. It is important to document any measures you take to help the patient in this regard. This would include things like choosing an appropriate, non-threatening location, allowing sufficient time to explain the issues carefully and to listen to the patient’s response, the presence of someone the patient trusts, the assistance of a speech therapist or any communication tools and visual aids you employ.

Remember, mental capacity is decision-specific, so the assessment should focus on the patient’s understanding and processing of information relevant to the decision in hand. Relevant information includes the nature of the decision, why a decision is needed and the likely effects of deciding one way or another, or making no decision at all. How you convey such information is important. It should be formulated in such a way as to make it as easy as possible for the patient to understand, using whatever tools and media are necessary to aid the patient in accessing the information.

To arrive at a decision, the patient must be able to do three things with the information:

  1. Understand it.
  2. Retain it.
  3. Weigh it.

The patient must then be able to communicate his or her decision. It is not always necessary to go into detail when explaining the relevant facts and options. Where the decision is unlikely to have serious consequences, if the patient can grasp the essentials in broad terms, they can be considered to meet the first criterion of understanding. The more serious the nature of the decision and its consequences, the more detailed the information you will need to share and the patient to comprehend.

The issue of retention of information can be difficult, especially if a patient has problems with short-term memory. There are two aspects of retention that you might need to address.

  1. Is the patient able to retain the information for long enough to weigh it in the balance and arrive at a decision?

    This might not be a problem if the decision in hand is quite straightforward and can be made quickly, but if it is a question that needs mulling over, the patient might be incapable of retaining the information for long enough to do so. Aids such as photographs, audio and video recordings, notebooks and posters may help the patient with the process. If it’s appropriate, enlist the help of relatives and carers to support the patient through the decision-making process.
  2. Is the patient able to make a decision, but then forgets about it?

    If so, all is not lost as long as the patient is consistent in their decisions. Consistency is tested by seeing if the patient makes the same decision when re-presented with the relevant information. If you are satisfied that the patient has a sufficient understanding of the relevant information, and can retain it long enough to make a decision, the next thing to assess is his or her ability to weigh the information.

What you should focus on here is not the outcome – ie, the actual decision, but on the process of getting there. Is the patient weighing the options in the context of his or her personal preferences, values and beliefs? Are those expressed values and beliefs consistent? (Remember, family members and close friends can be an invaluable source of information about the patient’s previously held beliefs, values and likely wishes.)

When questioning the patient during this part of the test, you will probably focus more on ascertaining his or her feelings than you did in your earlier testing of understanding. Try to arrive at an understanding of the patient’s own priorities (eg, how important is it to the patient to preserve his or her dignity? How highly does the patient value his or her independence? Is mobility a high priority? How about pain control?). Does the patient take these priorities into account when weighing his or her decisions in the balance?

Question 3: Can the patient communicate their decision?

Communication really belongs at the top of the list because it is not just the end point of the process (ie, the patient must be able to communicate his or her decision), but is a prerequisite of everything else that occurs. If you can’t communicate in a way that the patient understands, or if the patient can’t communicate with you, it’s just not possible to test his or her understanding, retention or weighing of information.

The most extreme example of this would be a patient in a coma, or in a persistent vegetative state. But in the vast majority of cases where the patient has a degree of mental capacity, some means of establishing communication is possible, even where the patient is severely incapacitated physically. They may be limited to indicating “yes” and “no”, but this limited means of communication should not, of itself, be considered sufficient reason to decide that they lack mental capacity.