Studies on neurochemical heterogeneity in healthy parents of schizophrenic patients.

Serum homovanillic acid (HVA), norepinephrine (NE), phenylalanine (Phe) and tyrosine (Tyr) have been examined in 80 healthy parents of schizophrenic patients and 26 normal control subject. Analysis of variance revealed a significant difference in serum HVA concentration among the three groups: the parents whose ill offspring became fairly well after neuroleptic treatment for more than three months (n = 33), those whose offspring were still actively ill after neuroleptic treatment (n = 33), and normal control subjects (F = 3.98, df = 2, 89, p < 0.05). The t-test showed that serum HVA was significantly higher in the parents whose ill offspring became fairly well after neuroleptic treatment (11.8 +/- 5.0 ng/ml) than in normal control subjects (8.7 +/- 3.5 ng/ml, p < 0.01), but was not significantly higher in the parents whose offspring were still actively ill (10.5 +/- 3.7 ng/ml, p > 0.05). There was a significant difference between the serum NE concentrations of the parents of female patients (515 +/- 224 pg/ml, n = 21) and those of male patients (401 +/- 186 pg/ml, n = 55, p < 0.05). No significant differences were found in the serum concentrations of Phe and Tyr. These results suggest that there may be neurochemical heterogeneity in the parents of schizophrenic patients, which may be involved in the response of schizophrenic offspring to neuroleptic treatment and in the gender differences of schizophrenia.