Relationship between therapeutic effect of risperidone,clozapine, chlorpromazine and pre and post treatment changes in glutamate level in patients with schizophrenia

Objective:To explore the effect of some antipsychiatric drugs on serum glutamate level in relation to therapeutic effects.Methods:60 patients were randomized to receive risperidone,clozapine,and chlorpromazine in specific dose for 8 weeks and their clinical symptoms were assessed using BPRS(Brief Psychiatric Rating Scale), SANS (Scale for Assessment of Positive Symptom),SAPS(Scale for Assessment of Positive Symptom) and WCST (Wisconsin Card Sorting Test).Serum glutamate content (SGC) was determined before and after treatment and normal serum glutamate concentration was obtained from 15 healthy volunteers.Results:The post treatment SGC for all drugs was significantly higher than that of pre treatment except chlorpromazine( P 0.01).The clinical effectiveness was positively correlated with the difference of SGCs in pre and post treatment groups of risperidone and clozapine.Conclusion:Glutamatergic system can be affected by risperidone and clozapine treatment and it may be related to improvement in psychiatric symptoms.