The law presumes that all persons are capable of guiding their own day-to-day lives, but the presence of various types and degrees of mental disability or mental incapacity can call this capability into question. When competency is convincingly demonstrated to be impaired, to the extent that decision-making requires input, persistent guidance, or outright control by some external entity, the civil courts might elect at that juncture to impose some form of “substituted judgment.” Substituted judgment undertakes to address three broad and potentially overlapping decision-making domains, described here with brief accompanying examples: prior judgment (regarding wills and other advance directives), present judgment (regarding informed consent and the corresponding right to refuse treatment), and future judgment (regarding guardianship and conservatorship). This chapter will explore each of these domains in detail, identifying the contributions mental health professionals can make to reliable and valid forensic assessment in this regard.

This chapter describes general principles in ethical decision-making, as well as the patient’s critical role in making decisions that are both medically and morally sound. When the patient no longer has capacity to participate in decision-making, various approaches to advance directives can be implemented. A morally appropriate and legally empowered surrogate decision-maker can be appointed; other advance directives could include DNR orders, a living will, or a durable power of attorney for health care. These may inform the discussion of the goals of care for an individual patient, leading to ethically acceptable actions for the patient, family, and medical team. These principles are then applied and discussed in specific cases: disclosing a diagnosis of dementia, substituted judgment and medical futility, and the provision of nutrition and hydration.