Urinary trace amine excretion and platelet monoamine oxidase activity in schizophrenia

The relationship between subtypes of schizophrenia classified by ICD-9 and 24-hour urinary β-phenylethylamine (PEA) and phenylacetic acid (PAA) excretion has been studied. Schizophrenia was divided into two types: paranoid and nonparanoid. Increased urinary PEA excretion was found in paranoid schizophrenics, but urinary PAA excretion did not show any significant difference between schizophrenics and normal subjects. A relationship between platelet monoamine oxidase (MAO) activity and urinary PEA excretion was found. These findings offer some indication that PEA may play a role in the pathogenesis of schizophrenia.