Relationship of symptomatology, gender, and antipsychotic drug treatment with plasma homovanillic acid in schizophrenia

AIM: To study the role of dopamine neurotransmission in schizophrenia and i ts drug treatment by assessing the relationship of plasma homovanillic acid (pHVA), a major central dopamine metabolite to various clinical parameters in schizophrenic patients. METHODS: pHVA was measured by high-performance liquid chromatography with electrochemical defection in a large cohort of b oth medicated and unmedicated DSM-IV schizophrenic patients. Prior to the m easurement of pHVA, the patients were rated on the schedule for the assessm ent of positive and negative symptoms (PANSS). RESULTS: (1) pHVA in 46 pati ents receiving antipsychotic drugs was decreased, and in 58 drug-free patie nts increased, (7.4 +/- 2.7) mug/L and (10 +/- 4) mug/L compared with a mat ched control group (9 mug/L +/- 3 mug/L, n = 62) (ANOVA F = 8.57, df = 2, P < 0.01), respectively. Within the drug-free group, pHVA was higher in the patients with a more negative symptom profile. (2) No significant correlati on of pHVA with overall SAPS or SANS scores was apparent in the drug-free p atients, although within the SANS subscales, a significant relationships to anhedonia-asociality (r = 0.32, P < 0.05) was apparent. The male drug-free patients showed a positive correlation of pHVA with negative symptoms (r = 0.42, P < 0.05) while females showed no significant relationship with any PANSS subscales. CONCLUSION: The results suggest that an increased dopamine rgic metabolism is apparent in ( male) schizophrenic patients with predomin antly negative symptoms, supporting reports that this change in neuronal ac tivity may be related to the neuropathological abnormalities seen in the di sease, which may differ between males and females. Such neuronal deficits o f developmental origin may thus result in an elevation/disinhibition of cen tral dopamine metabolism in schizophrenia.