Enrolling decisionally impaired adults in clinical research.

Progress in diagnosing, treating, and preventing medical conditions that impair decision-making abilities depends on clinical research involving individuals who may be either unable to or have diminished ability to give informed consent. Such research, however, raises ethical concern and controversy about the potential exploitation of these vulnerable individuals. This article addresses a range of ethical and practical issues concerning the enrollment of adults who are decisionally impaired, and those at risk of becoming so, in clinical research. These include (1) the relationship of decision-making capacity to competence, and the framework for determining competence in adults receiving clinical care and making treatment decisions for those who lack competence; (2) the differences between clinical practice and clinical research that influence the criteria for permissible research involving incompetent adults and the applicability of the framework guiding treatment decisions to clinical research decisions; and (3) the regulatory framework developed to guide the ethical participation of children in research and its applicability to determining the scope and limits of research with incompetent adults.