The Mental Health Act Amendment Act 1964 (Act No.30/1964) commenced 22 October 1964. Its full title is ‘An Act to amend the Mental Health Act, 1935-1963’. Among others, it amends the title of the principal Act, replacing ‘mentally defective persons’ with the words ‘persons who are mentally ill or intellectually retarded’. It also amends the definition of ‘institution’, ‘intellectually retarded’, ‘mentally defective person’, ‘superintendent’ and ‘training centre’.