The right of patients to accept or refuse recommended treatment requires careful reassessment when their decision-making capacities are called into question. Patients must be informed appropriately about treatment decisions and be given an opportunity to demonstrate their highest level of mental functioning. The legal standards for competence include the four related skills of communicating a choice, understanding relevant information, appreciating the current situation and its consequences, and manipulating information rationally. Since competence is a legal concept and can be formally determined only in court, the clinical examiner's proper role is to gather relevant information and decide whether an adjudication of incompetence is required. Treatment for impairment of mental functioning can sometimes restore patients' capacities, making it unnecessary to deprive them of their decision-making powers.