Heterogeneity in plasma homovanillic Acid levels in schizophreniform disorder.

Plasma homovanillic acid (pHVA) levels were estimated in 20 cases of schizophreniform disorder, 14 cases of schizophrenia 'on medication' and 17 cases of schizophrenia 'off medication'. A bimodal distribution of pHVA was seen in schizophreniform disorder subjects, suggesting heterogenous groups in terms of dopaminergic function. No significant difference in the pHVA values was seen in the 3 groups, nor was there a relationship between the severity of the illness and the pHVA values; these results suggest plasticity of the dopaminergic system to neuroleptics.