Etiologic heterogeneity of the psychoses: Is there a dopamine psychosis?

The distribution of drug-free plasma homovanillic acid (pHVA) concentrations was studied in a sample of psychotic patients, some of whom were selected for good prognostic features. Baseline pHVA was bimodally distributed, suggesting two different patient populations. The high-pHVA patients showed periods of better functioning and/or fewer symptoms 5 years before admission (p<.05) and had a more rapid (p<.05) and complete (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 psychotics 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.