What is advance directive?
advance directive is A mechanism by which a competent individual expresses his or her wishes should circumstances arise in which he or she no longer is able to make rational and sound decisions regarding his or her medical treatment. Usually ‘advance directive’ refers to orders for withholding and/or withdrawing life support treatments at the end of life, made by writing living wills and/or granting power of attorney to another individual.
source: A GLOSSARY OF TERMS FOR COMMUNITY HEALTH CARE AND SERVICES FOR OLDER PERSONS. World Health Organization, 2004.