In order to investigate the biological characteristics of deficit syndrome in schizophrenia (Carpenter et al 1988), we examined cerebroventricular ratios (CVRs) and plasma concentrations of homovanillic acid (HVA) in a group of schizophrenic inpatients with deficit syndrome (n = 20) and in a control group of age- and sex-matched schizophrenic inpatients without deficit syndrome (n = 20). Symptoms and intelligence levels were measured using the Brief Psychiatric Rating Scale (BPRS) and the Wechsler Adult Intelligence Scale (WAIS), respectively. Patients in the deficit group had significantly higher CVRs as well as significantly elevated plasma HVA concentrations when compared with patients in the nondeficit group. We also found that the mean total WAIS score in the deficit group was significantly lower than that in the nondeficit group. These findings suggest the biological heterogeneity of schizophrenia. Increased central dopaminergic turnover, as indicated by higher plasma HVA concentrations, may partially account for the pathogenesis of deficit syndrome.