The present invention relates generally to a method of modulating glutathione metabolism in the central nervous system of mammals and to agents for use therein. More particularly, the present invention relates to a method of up-regulating glutathione metabolism in the central nervous system by up-regulating levels of glutathione precursor molecules. The method of the present invention is particularly useful, inter alia, in the treatment and/or prophylaxis of conditions characterised by aberrant, unwanted or otherwise inappropriate central nervous system oxidation homeostasis including, but not limited to, schizophrenia.
