PLASMA HOMOVANILLIC-ACID AND TREATMENT RESPONSE IN A LARGE GROUP OF SCHIZOPHRENIC-PATIENTS

Plasma levels of homovanillic acid (pHVA), a metabolite of dopamine, w ere measured in ninety-five Chinese schizophrenic patients free of neu roleptics for at least four weeks. These patients were treated with cl assical antipsychotics for six weeks. Pretreatment pHVA was positively correlated with the subsequent clinical response (r = 0.408, p < 0.00 01). Good responders (BPRS improvement greater-than-or-equal-to 50%, n = 47) had higher pretreatment pHVA levels than poor responders (BPRS improvement < 50%, n = 48) (15.7 +/- 8.4 ng/ml versus 9.9 +/- 3.7 ng/m l, p < 0.0001). A higher than 15 ng/ml pretreatment pHVA level was ass ociated with a more consistent clinical response to the subsequent tre atment. Using a pHVA level of 12 ng/ml as a demarcation point, 72% of patients (34 of 47) who had pHVA greater-than-or-equal-to 12 responded whereas 65% (31 of 48) who had < 12 did not respond (chi-square = 13. 02, p < 0.0001). These results suggest that higher pretreatment pHVA l evels may predict a better clinical response to antipsychotics. Based upon the pHVA findings, two hypothetical subtypes of schizophrenia are proposed.