title: The ratio of plasma phenylalanine to other large neutral amino acids is not a risk factor for tardive dyskinesia.
abstract: The ratio of the plasma concentration of phenylalanine (PA) to the sum of the plasma concentrations of other large neutral amino acids (LNAA) was calculated in 26 chronic, in-patient schizophrenics who met diagnostic criteria for tardive dyskinesia and 22 patients who did not. No difference in the PA/LNAA ratio was found between the two groups. Small positive correlations were found between age and both PA/LNAA ratio and tardive dyskinesia. Neuroleptic dose correlated negatively with both age and plasma PA/LNAA ratio. No support was found for previous reports of increased plasma PA/LNAA ratio in schizophrenic patients with tardive dyskinesia.
authors.affiliation: Department of Psychiatry, Royal Edinburgh Hospital, Morningside Place, Edinburgh EH10 5HF.
authors.forename: J
authors.initials: J
authors.lastname: Geddes
authors.forename: G
authors.initials: G
authors.lastname: Reynolds
authors.forename: J M
authors.initials: JM
authors.lastname: Rattenbury
authors.forename: M
authors.initials: M
authors.lastname: Peet