Capacity, belief and impairment of the mind or brain

In Re T (Adult: Refusal of Treatment) [1992] Lord Donaldson MR held that the right to decide one's fate presupposed an ability or capacity to do so. This led his Lordship to argue that mental capacity was the key to a person's autonomy, as nurses are bound by the decisions of a capable adult but can override autonomy and make decisions or act in the best interests of a person where capacity has been rebutted.

In Re C (Adult: Refusal of treatment) [1994] the High Court was required to determine if a person living with paranoid schizophrenia lacked capacity to refuse an amputation of his gangrene-infected leg. In the case Justice Thorpe (at 292) considered how a person with capacity makes a decision and held that there were three stages in the process:

Expert evidence in the case particularly focused on whether Mr C did not believe that his death was imminent and whether this was due to his mental disorder, which included a false belief that he was medically qualified.