Commentary: Willingness and competence of depressed and schizophrenic inpatients to consent to research.

Interest in the characterization and assessment of decisional capacity in medicine began to develop in the mid-1970s, in the wake of the near-universal endorsement of the legal doctrine of informed consent earlier in the decade. Early commentaries recognized the importance of identifying generally accepted criteria for decisional capacity as a prerequisite to valid assessment, and for a number of years this was the focus of most scholarly attention. By the end of the 1980s, however, a rough consensus had evolved regarding those functions essential for decisional capacity: the abilities to understand the relevant information, appreciate its implications for one’s own situation, rationally manipulate the information (often referred to as reasoning), and express a choice. This conceptualization was applied to capacity for treatmentand research-related decisions, and it is likely to be applicable to other kinds of decisional capacity as well. Assessment of capacity, a task often assigned to psychiatrists, had meanwhile evolved in an unsystematized fashion, with attending physicians often passing on their idiosyncratic approaches to a new generation of residents. To no one’s surprise, studies suggested poor interrater agreement among physicians for these determinations. Efforts to carry out capacity assessments for research purposes were similarly handicapped by the absence of a standardized approach. Each research team developed its own instruments, often based on idiosyncratic criteria, making comparisons across studies all but impossible and often leaving readers uncertain how much validity to accord to the methods used and the results reported. The largest study to date of decisional capacity, which focused on consent to treatment by patients with psychiatric and medical disorders, is the MacArthur Competence Assessment Study, which Thomas Grisso and I conducted in the early 1990s. Even more important than any of the substantive findings of the study, reported in a series of papers in the mid-1990s, –12 were its major spin-offs: the MacArthur Competence Assessment Tools for Treatment and Clinical Research (MacCAT-T and MacCAT-CR). Designed to permit efficient structured assessment of decisional capacity that is nonetheless individualized to the particular situation of each patient or research subject, the MacCATs have become a favorite tool of researchers looking to characterize the decisional capacities of populations of patients or research subjects. At this early stage in the evolution of research and practice related to capacity assessment, it seems unlikely that any existing instrument will constitute the final word on the matter. But the popularity to date of the MacCAT instruments means that for the first time we have a body of roughly comparable data from multiDr. Appelbaum is A.F. Zeleznik Distinguished Professor and Chair of Psychiatry and Director, Law and Psychiatry Program, University of Massachusetts Medical School, Worcester, MA. Address correspondence to: Paul S. Appelbaum, MD, Department of Psychiatry, University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655. E-mail: appelbap@ummhc.org