Determination of Decision-Making Capacity

Decision-making capacity refers to the ability to make a specific decision. Making a valid decision requires understanding the facts presented, appreciating the nature of the decision to be made, mentally manipulating the information rationally, and communicating the decision. The complexity of the decision is a major determinate of how difficult it is to make the decision. Physiologic changes with aging, psychological changes, medication effects, and clinical syndromes, particularly dementia, common in aging all can affect decision-making ability. Clinicians are often required to assist in determining decision-making capacity, and many instruments have been developed to assist in this determination. Common categories of decisions include ability to consent to or refuse medical or psychiatric treatment, ability to decide to remain living at home instead of a more institutional setting, capacity to sign contracts, wills, or make other financial decisions, capacity to consent to sexual relations or marry, and capacity to consent to research. Factors that can complicate determination of decision-making include fluctuating levels of cognitive functioning from delirium, difficulty processing or producing speech in aphasia, and external factors that produce undue influence.