This is the first survey on how physicians, treating patients with AN in Japan, the US, and UK, assess the mental capacity of patients with AN.
Patients with AN often refuse treatment, although it may seem irrational from a general view. Mental capacity is generally evaluated by four elements, which include understanding, appreciation, reasoning, and expression , and most patients with AN who refuse treatment show mental capacity when evaluated from these four points of view [6, 15]. However, in this survey, ~ 20–30% of physicians in Japan, the UK, and US rated patients with AN who refused treatment as having impaired mental capacity. While it is possible that physicians are assessing the conventional four components of mental capacity as impaired in patients with AN who are refusing treatment, it is also possible that physicians treating patients with AN use other components.
As a result of asking physicians whether they respect the patient's treatment refusal, approximately 2/3 of physicians in Japan, 1/2 in the UK, and 1/3 in the US said that they do not respect the decision. Despite accepting that the patient has mental capacity, these physicians are considered to be placing the physician's ethical duty of beneficence to protect the patient's life above their ethical duty of respect for autonomy, which is to respect the patient's self-determination. In particular, Japan showed significantly less respect for self-determination than the UK and the US, which may be due to the fact that in Japan, in addition to the long-standing paternalism [16, 17], there is a legal system that allows for therapeutic intervention with mentally ill patients as long as the patient’s guardian consents . It is possible that physicians in Japan have a different attitude toward the mental capacity of patients with AN refusing treatment than in the UK and US.
Japanese physicians were significantly different than their counterparts in the US and UK in terms of items to focus on when assessing mental capacity of patients with AN. Japanese physicians focus on “short-term memory,” “ ability to express a choice or preference,” “ability to understand medical information given,” “ability to appreciate medical information as it relates to oneself,” “ability to process reasonable information,” and “ability to weigh competing factors” out of 10 items when assessing mental capacity. Of these, “ability to express a choice or preference,” “ability to understand medical information given,” “ability to appreciate medical information as it relates to oneself,” and “ability to process reasonable information” are components of the mental capacity identified by Applebaum and Grisso , and “short-term memory” is also an essential component of the “ability to understand.” The fact that these items were not emphasized when assessing mental capacity suggests that a standardized assessment of mental capacity may not be performed in Japan. One possible reason for this is that in Japan, the distinction between the capacity to make clinical decisions and the capacity to be responsible in judicial psychiatric evaluations is not clearly defined , and physicians may not accurately understand the concept of mental capacity as the capacity to make decisions in clinical practice. A few clinicians may confuse the assessment of cognitive function with the assessment of decision-making capacity as it is in Japan . The results showed that Japan may differ from the UK and US in terms of the evaluation methods of mental capacity.
The UK tended to place significantly more emphasis on “short-term memory” and “ability to weigh competing factors” when assessing mental capacity, compared not only with Japan but also with the US. This may be since the Mental Capacity Act in the UK lists “understand the information relevant to the decision,” “retain that information,” and “use or weigh up that information as part of the process of making the decision” as the evaluation items for mental capacity , which refer to memory retention and the weighting of information.
The difference in the emphasis placed on the factors that are important when assessing mental capacity was examined between physicians in the UK and US who reported that patients with AN who refuse treatment have mental capacity and those who reported that they do not. The results showed that physicians who thought patients with AN did not have mental capacity placed significantly more importance on “level of pathological values” than those who considered they did, while those who thought patients with AN had mental capacity placed significantly more importance on “ability to express a choice or preference” than those who consider they did not. No differences were found outside of these items.
Most items listed are items of the Appelbaum and Grisso's mental capacity assessment tool commonly used in the assessment of mental capacity and items listed in the Mental Capacity Act. No differences were found in the items normally used to assess mental capacity. Some physicians regarded some patients as having the mental capacity and others did not, despite lack of difference in these items, which is consistent with the results reported by Elzakkers who found that the concordance between assessments by MacCAT-T and clinicians was not high .
The ethical attitude of physicians who value patient autonomy may give rise to a tendency to evaluate patients with AN as having mental capacity to make decisions whenever possible. As a result, physicians who assess mental capacity may place more weight on whether the patient with AN expresses any preference or choice to do so.
Since patients with AN tend to be evaluated as having mental capacity under the usual method of assessing mental capacity [6, 15], when a patient with AN refuses treatment, the physician is forced to choose between a paternalistic response that gives priority to treatment against the patient's wishes in accordance with the duty of beneficence, or a response that respects the patient's self-determination and gives up treatment. However, by adding “level of pathological values” to the evaluation item for the presence or absence of mental capacity, it will be possible to evaluate a patient who refuses treatment despite a life-threatening situation as having impaired his or her mental capacity. This is because the refusal to treat patients with AN is due to psychopathological values of not wanting to eat even if you were dead, brought on by the fear of becoming obese . As a result, the ethical dilemma of whether to respect the patient's self-determination or prioritize the protection of the patient's life can be avoided. Tann et al.  point out the influence of “belief” and “change in patient’s value” on assessing mental capacity y of patients with AN. Moreover, psychiatrists may be assessing the mental capacity of patients with AN in a different way than they normally do , and the key point of their assessment method may be the “level of psychopathological values”.
It may be necessary to add levels of psychopathological values to the assessment of mental capacity is necessary in relation to obesity fears and emotional disturbances in patients with AN. Elburg et al.  pointed out that MacCAT-T places more emphasis on the cognitive aspects of decision making, and that the problem in decision making of patients with AN is the inability to make rational decisions, which is affected by the inability to control emotions. This emotional disturbance is typically a strong fear of treatment and anxiety about recovery on the grounds of losing one's identity , which is thought to be linked to pathogenic psychopathology represented by the fear of gaining weight or of becoming fat . However, even if emotional disturbances resulting from psychopathology do affect decision-making, the question arises of whether they can be added to the assessment of mental capacity. The ability to make decisions is the basis of mental capacity, and if the patient has the mental capacity, he or she must be respected as an autonomous being; oppositely, if the patient has impaired mental capacity, he or she must be supported to approach an autonomous being . If the patient has the mental capacity, as an autonomous being, the physician is ethically required to respect the patient's self-determination. This concept of autonomy is strongly influenced by Kantian philosophy and assumes that a rational person can deliberate and govern his or her actions . For example, when a man who has become desperate due to shock and fear upon discovering that he is ill, insists on being left alone even though he has a good chance of being cured, it is not an ethical decision to regard his insistence as self-determination and accept it as is according to the principle of respect for autonomy. This is because the principle of respect for autonomy has an active duty, and the physician has an obligation to assist the patient in making decisions in a rational and personable manner. In other words, when a person is making decisions governed by emotion, we believe that he or she is not fully exercising his or her autonomy. Therefore, when psychopathology causes emotional disorders and these emotions strongly influence decision making, the patient with AN is considered to have lost his or her autonomy. Since mental capacity is related to the patient's autonomy, it is reasonable to evaluate a patient with AN who has been severely affected by psychopathology as having impaired mental capacity.
This study has some limitations. First, the Japanese survey was mailed to physicians who were members of the Japanese Society for Eating Disorders, while the UK and US surveys were web-based surveys of physicians who were members of academic societies and registered with medical networks. Although responses were obtained from physicians who treat patients with AN in all three countries, it is undeniable that the difference in survey methods may have affected the results. Second, the sample size was small, making representativeness problematic. Third, the survey was a multiple-choice questionnaire, which may have overlooked the possibility that physicians treating patients with AN may place importance on items that are not included in the options when evaluating their mental capacity. Finally, the vignette-basis for this study is that the surveyed clinicians’ conclusions are not based on a robust clinical assessment but rather on an extremely limited understanding of the patient. The study results and differences seen may reflect surveyors’ idiosyncratic responses to the case and not usual clinical practices and thus limits the generalizability.
In the future, it may be necessary to conduct a survey of physicians treating patients with AN, focusing on the reasons for adding the level of psychopathological values identified in this study to the assessment of mental capacity, and to evaluate what kind of psychopathological values are important to them.