Bioethics for clinicians: 3. Capacity.

In the context of patient consent, "capacity" refers to the patient's ability to understand information relevant to a treatment decision and to appreciate the reasonably foreseeable consequences of a decision or lack of decision. A person may be "capable" with respect to one decision but not with respect to another. Clinicians can usually identify patients who are clearly capable or incapable, but in some cases a clinical capacity assessment is required. Such assessment may consist of cognitive status testing, general impressions of capacity or specific capacity assessment. Specific capacity assessment, in which the clinician evaluates the patient's ability to understand pertinent information and appreciate its implications, is probably the optimal method. When conducting a specific capacity assessment, the clinician must ensure that the disclosure of information is effective and must evaluate the patient's reason for his or her decision. If the assessment suggests that the patient is incapable, further assessment is generally recommended.