ETIOLOGIC HETEROGENEITY OF THE PSYCHOSES - IS THERE A DOPAMINE PSYCHOSIS

The distribution of drug-free plasma homovanillic acid (pHVA) concentr ations was studied in a sample of psychotic patients, some of whom wer e selected for good prognostic features. Baseline pHVA was bimodally d istributed, suggesting two different patient populations. The high-pHV A patients showed periods of better functioning and/or fewer symptoms 5 years before admission (p<.05) and had a more rapid (p<.05) and comp lete (p<.001) subacute neuroleptic response than lower-pHVA psychotics . High-pHVA psychotics did not differ in other aspects od demographics or clinical presentation from lower-pHVA psychotics. Compared to the general population, there were more psychotics in the families of high -pHVA patients (p<.005). Rapid antipsychotic response by high-pHVA psy chotics is consistent with blockade of the effects of excess synaptic dopamine at D-2 receptors for these patients. Results are discussed in the context of the syndromic heterogeneity of the psychosis. (C) 1997 American College of Neuropsychopharmacology.