More than half of young adults soon unwittingly change their minds about decisions they make governing future life-saving medical treatment for themselves, a new study has found.
Asked if they would want to be resuscitated or given drugs in a hypothetical life-threatening event, most of the study subjects had forgotten their decisions only a few months later and gave different instructions.
The finding, to be presented at the American Psychological Society convention in Los Angeles, suggests that advance directives - or so-called living wills - made by young people should be reviewed regularly.
It comes in the aftermath of the recent controversy surrounding the death of a severely brain-damaged Florida woman, Ms Terri Schiavo.
Ms Schiavo had left no prior written instructions about the extent of medical care she wanted, prompting a much-publicised family legal battle and fierce political debate in the US about how long life-support systems should be used.
The new study was carried out by Dr Stefanie Sharman, UNSW psychology researcher and her colleagues, Maryanne Garry (Victoria University of Wellington), Peter Ditto and Elizabeth Loftus (University of California at Irvine). The team interviewed 31 young adults - aged 18 to 22 years - on two occasions, four months apart.
Respondents were asked whether or not they wanted each of four treatments (antibiotics, cardio-pulmonary resuscitation, gall-bladder surgery, and tube feeding) in nine hypothetical medical scenarios. The scenarios included Alzheimer's disease, emphysema, coma, paralysis and cancer.
In the second interview, respondents were asked whether they thought their decisions had changed. They were asked as well to give reasons for each treatment decision and their mood was measured during interviews.
"We found that 58 per cent of the people surveyed changed at least one of their decisions in the space of four months, without realising it," says Dr Sharman. Other key findings were that: