Decisional capacity is decision specific (e.g. one might be able to choose what one wants for lunch but not whether or not a surgical interventions is appropriate) and it can wax/wane over time (e.g. directly following TBI I may not have decisional capacity, but may regain it over time).

Decisional capacity depends on the following (Applebaum 2007):

1. ability to communicate a choice
2. ability to understand the relevant information
3. ability to appreciate consequences
4. ability to reason about treatment choices.

Decisional capacity also comes in degrees and requires support. A number of things can affect one’s ability to demonstrate capacity or be capable (e.g. language barriers, fear of medical professionals, depression, etc.). But many patients with internal or external impairments that affect decisional capacity in the above regards can be capable with sufficient support. This is often called supported decision making and is growing formal legal support/actualization across the country.

• Medical Ethics Website UWSOM: Advance Care Planning
• Applebaum, PS. Assesment of Patients’ Competence to Consent to Treatment, NEJM, 2007, 357:1834-40.
• http://supporteddecisionmaking.org/