The survey by FindLaw.com, a legal information website, found 61 percent of U.S. adults said they have no living will, also known as a healthcare directive or directive to physicians.
A living will is a document in which a person can indicate his or her instructions in advance as to what medical treatments he or she wishes to receive in the event he or she is unable to communicate those wishes due to terminal illness or permanent unconsciousness.
Under certain conditions, it permits doctors to withhold or withdraw life support systems. In the absence of a living will, medical care decisions are generally made by a spouse, guardian, healthcare agent, or majority of parents and children.
However, if family members and doctors have difficulty deciding on medical care, the matter could be decided in court, FindLaw.com says.
"Without a living will, there is no clear directive for families and medical professionals to follow in terms of what types of care should be administered or withheld in the event that you become incapacitated or unable to communicate your medical treatment preferences," Stephanie Rahlfs, an attorney and editor with FindLaw.com, said in a statement. "Living wills and healthcare directives let you specify which treatments you want, and who will make decisions when you're not able."
No survey details were provided.