ABSTRACT
This is the first of three papers reporting the results of the MacArthur Treatment Competence Study, a project designed to develop reliable and valid information with which to address clinical and policy questions regarding the abilities of persons with mental illness to make decisions about psychiatric treatment. Four commonly applied legal standards for determining decision-making competence are described: abilities to communicate a choice, understand relevant information, appreciate the nature of the situation and its likely consequences, and rationally manipulate information. Previous research related to the capacities of persons with mental illness in relation to these standards is reviewed and critiqued. The principles underlying the design of the MacArthur Treatment Competence Study are described.
