Possible Interaction: Methionine and Monoamine Oxidase Inhibitors

“IN 1961 POLLIN, CARDON and KETY’ reported that a proportion of chronic schizophrenic patients who received methionine given in conjunction with a monoamine oxidase inhibitor showed an acute psychosis followed in some cases by an amelioration of their chronic schizophrenic symptoms.”

“The transmethylation hypothesis of schizophrenia was reviewed with considerations that large doses of methionine when combined with a monoamine oxidase inhibitor lead to exacerbation of psychotic symptoms in a significant percentage of chronic schizophrenic patients.”

“Large doses of methionine prescribed with amine oxidase inhibitors produced behavioural changes in schizophrenics (Pollin, Cardon, and Kety, 1961; Park, Baldessarini, and Kety, 1965), and it has been suggested that there is an aetiological link between schizophrenia and disorders of transmethylation-for example, in the review by Smythies (1967).”

“ORAL administration of a large amount of methionine to schizophrenic patients who had been treated with a monoamine oxidase inhibitor ( MAOI ) was reported to produce psychic symptoms which have been interpreted either as an intensification of schizophrenic symptoms or as superimposed toxic symptoms1–4.”

“Pollin, Cardon and Kety3 observed hyporeflexia and extensive mood changes in schizophrenic patients who received tryptophan, or methionine in addition to a monoamine oxidase inhibitor.”