The Mental Health Amendment Act 1981 (Act no.84/1981) with the full title “An Act to amend the Mental Health Act 1963 for the purpose of making further provision with respect to persons detained in a special institution within the meaning of that Act” amended the Mental Health Act 1963 (Act no. 63/1963) from 1981 until its repeal by Statute Law Revision Act 1991 (No.46) on 19 December 1991.