Published online by Cambridge University Press: 09 July 2009
Disordered amine metabolism is frequently suggested as being of aetiological significance in schizophrenia. The present study investigates the effects of loading doses of the cate-cholamine precursor L-tyrosine in this illness. Groups of schizophrenic and control subjects were given loading doses of L-tyrosine after which plasma tyrosine levels and excretion of some tyrosine metabolities were measured. In only one parameter, excretion of free p-hydroxyphenylacetic acid, was any significant difference observed between the groups. The study is discussed in relation to some of the biochemical theories advanced from time to time for schizophrenia.