Abstract

Around the world, we now face a serious ageing society. The population of the elderly with dementia is sharply increasing as people live longer. We thus need some effective social design to protect the elderly that have dementia. In the current legal system, we have a lasting power of attorney (LPA), adult guardianship system (AGS), and elder abuse/consumer laws to protect the property and affairs of elderly with dementia. However, those methods are not adequate. In the twenty-first century, people have the right to lives providing reasonable satisfaction. In this sense, the most important value for people is “autonomy.” In order to respect the autonomy of the elderly who have dementia, we need a supported decision-making (SDM) method to understand their will and preferences and to implement their wishes. There are many projects around the world attempting to establish an effective SDM method, but no institutional method has been established. One negative risk of SDM is undue influence. Guiding principles, such as a soft law, would be practical and ethical to regulate SDM because regulating SDM through a hard law might be unworkable. We need effective guiding principles, possibly ad hoc auditing or registration with an authority, to regulate the risk of undue influence in SDM.