Should dementia sufferers be punished for past crimes?

This paper examines whether we ought to prosecute historic offences committed by people who have subsequently developed dementia. Currently, a person with dementia might avoid conviction on the basis of their currently diminished capacity. They may be unfit to plead, for example. The problem is that advanced dementia may undermine persistence of personal identity. Once someone develops dementia, they may no longer be the person who committed the crime. If so, they would not need to be excused for their offending. They would simply not be liable. If we think persistence of personal identity is based on psychological factors – as most of us do – a person with advanced dementia will not be the same person as the one who committed the crime. They will not deserve prosecution, never mind punishment. This issue has been overlooked by legal theorists. Although much has been written on the legal significance of dementia, it has been primarily in the context of advance directives or decision-making capacity. I will argue that advanced dementia is a challenge to criminal responsibility.