Ultraviolet-absorbing urinary components of mentally retarded children and schizophrenic adults.

Urinary excretion of ultraviolet-light-absorbing end products of metabolism was studied in mentally retarded children and schizophrenic adults. Excretion of the major end product of pyrimidine metabolism, pseudouridine (5-ribosyluracil), and one of the catabolic derivatives of nicotinic acid, N -methyl-2-pyridone-5-carboxamide, were both found to be depressedin more than half the mentally retarded children and all the schizophrenic adults studied. In addition, a number of previously unidentified components have been found in both types of mental abnormality, as well as in control subjects, some of which components appear to be present in abnormal quantities.