The law recognizes that adults—in most states, people age 18 and older—have the right to manage their own affairs and conduct business, including the right to make health care decisions. Emancipated minors are people below the age of adulthood (usually 18) who are also considered legally capable. The definition of this group varies by state but generally includes minors who are married or who are in the armed forces or who have obtained a court decree of emancipation.

Legal incapacity (or incompetency): Legal capacity and all the rights that go with it remain in effect until death. To establish legal incapacity, a court of law must determine that a person can no longer manage personal affairs in his or her own best interest and court intervention is necessary to protect the person. Doctors cannot determine legal incapacity. The legal proceeding is usually called a guardianship or conservatorship proceeding. Legal requirements for declaring incapacity vary by state. However, the following are typically required:

• A disabling condition (for example, intellectual disability, a mental disorder, dementia, a medical disorder that affects thinking or awareness, or chronic use of certain drugs)
• A lack of mental (cognitive) ability to receive and evaluate information or to make or communicate decisions
• An inability to meet essential requirements of physical health, safety, or self-care without protective intervention by someone
• A finding that guardianship or conservatorship is the only feasible way to protect a person

Health care practitioners, even if they think the person is incapable of making a decision, cannot override the person's expressed wishes unless a court declares the person legally incapacitated.

Today, state laws favor the term “incapacity” rather than “incompetency” and define the term as task-specific—that is, every task requires different capabilities to accomplish. For example, a person may be declared legally incapacitated regarding financial affairs, yet still retain legal capacity to make medical decisions or decisions about where to live. A finding of legal incapacity by a court of law takes away all or part of a person's right to make decisions. Legal incapacity normally results in the appointment of a guardian or conservator to make necessary decisions for the person.

Clinical incapacity: Clinical incapacity to make health care decisions is the medical judgment of a qualified doctor or other health care practitioner who determines a person is unable to do the following:

• Understand his or her medical condition or the significant benefits and risks of proposed treatment and its alternatives
• Make or communicate appropriate medical decisions

A person in a coma cannot make any decisions, whereas a person with a severe language problem may be able to make decisions but may be unable to communicate them. People with mild dementia may think clearly enough to understand discussions with their doctors and make some medical decisions. Also, clinical incapacity is not necessarily permanent. People who are intoxicated, delirious, comatose, severely depressed, agitated, or otherwise impaired are likely to lack the capacity to make health care decisions but may later regain that capacity. A person's ability to carry out a decision is also important for doctors to assess. For example, a person with a broken leg may be able to make decisions (for example, to leave the hospital) but be unable to carry them out. Providing the necessary support to carry out a decision becomes an important goal of care.

People with dementia may require an evaluation of their level of cognition, memory, and judgment before their doctors can proceed with medical care. Likewise, a clinical evaluation of the person's ability to conduct major legal and business transactions may be needed before a lawyer or accountant can proceed with transactions. For medical decisions, if doctors find that a person lacks capacity, they turn to someone with the authority to act as substitute decision maker. This process of making health care decisions for people who cannot make decisions for themselves is rarely litigated in court. However, if the person or other appropriate party objects to a particular medical decision or to the determination of clinical incapacity, the courts may become involved. A doctor cannot go against the person's wishes unless a court declares the person legally incapacitated.

Last full review/revision December 2012 by Charles Sabatino, JD