Abstract
The law in New South Wales by which murder may be reduced to manslaughter through the defence of diminished responsibility has been reformed by the Crimes Amendment (Diminished Responsibility) Act 1997 (NSW). The new defence focuses upon the concept of “substantial impairment by abnormality of mind” as the criteria for determining whether the accused lacked the requisite degree of criminal responsibility for murder. The amendment also introduces notice provisions with which the accused must comply in order to avail him or herself of the benefits of the section. The amendment was preceded by a detailed review of the law by the New South Wales Law Reform Commission. The article examines the new law within the context of this background.