Neuropsychopharmacology : official publication of the American College of Neuropsychopharmacology
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Neuropsychopharmacology · May 1989
Free and conjugated plasma homovanillic acid in schizophrenic patients.
It has recently been suggested that the plasma level of homovanillic acid (HVA) may provide an index of central dopaminergic activity in humans. Clinical studies have shown that in schizophrenic patients, plasma HVA levels increase with the severity of psychopathology. However, these studies only considered the plasma free HVA fraction whereas investigations on conjugated HVA in humans are sparse and results remain controversial. ⋯ No significant correlations were observed between plasma HVA levels and the clinical features of schizophrenic patients rated by various psychiatric scales. These findings suggest that there is an imbalance between plasma free and conjugated HVA in schizophrenic patients, who present an increase in total HVA when compared with controls. Paranoid schizophrenic patients, who present mainly positive symptoms, show the most marked plasma free/conjugated HVA imbalance.