The specific therapeutic effect of lithium salts in the treatment of the manic phases of manicdepressive psychosis was first reported by Cade (1949) and has been confirmed in a number of studies since (Schou, Juel-Nielson, Strömgren and Voldby, 1954; Maggs, 1963; Hartigan, 1963). In view of the claims made by Baastrup (1964) and more recendy by Baastrup and Schou (1967) that lithium also has a prophylactic action against both manic and depressive phases of manic-depressive psychosis it is likely that lithium salts will be used increasingly by psychiatrists.