Advance directives, or living wills, may not effectively honor end-of-life wishes because life-sustaining treatment preferences often change without people being aware of the changes, according to a new study co-authored by UC Irvine researchers Peter Ditto and Elizabeth Loftus.

False memories can play a significant role in the discrepancy between an individual's true preferences for end-of-life treatment and what is instructed in their living will. Life-sustaining treatment preferences often change as people age or experience new health problems, and advance directive forms typically remind people of their right to update their directives if their wishes change. This assumes that people recognize when their wishes about end-of-life treatment have changed, and remember that their current wishes are different from those documented in their living will.

"Living wills are a noble idea and can often be very helpful in decisions that must be made near the end of life. But the notion that you can just fill out a document and all your troubles will be solved, a notion that is frequently reinforced in the popular media, is seriously misguided," said Peter Ditto, professor of psychology and social behavior at UCI.

In research reported in the current issue of the American Psychological Association journal Health Psychology, a sample of 401 adults older than 65 were interviewed about which life-sustaining treatments they would want if they were seriously ill. They were interviewed again 12 months later to test their recall of earlier decisions. About one-third of participants changed their wishes regarding medical treatment such as CPR and "tube feeding" over the course of the year, and in 75 percent of these cases, participants falsely remembered that their original views on the issues matched their new ones.

Interviewers also talked to individuals empowered to make medical decisions if the study subjects were no longer able. These potential surrogate decision makers were even less sensitive to changes in their loved one's wishes, showing false memories in 86 percent of cases.

"On a policy level, these results suggest that living wills should have an 'expiration date.' People can't be counted upon to update their directives as their wishes change because they often have no awareness that their wishes have changed," Ditto said. "On a more personal level, our research stresses the importance of maintaining an ongoing dialogue among individuals, their families and their physicians about end-of-life treatment options," he continued.

The study was conducted by Ditto, Loftus, Maryanne Garry of Victoria University of Wellington, Jill A. Jacobson of Queen's University and Stefanie J. Sharman of the University of New South Wales.