A comparison of clozapine to chlorpromazine affecting serum glutamate levels and their relationship with clinical efficacy in schizophrenia

Objective To evaluate the effects of clozapine and chlorpromazine on serum glutamate(Glu) levels and their relationship with the therapeutic effectiveness.Methods Sixty inpatients with schizophrenia were treated with a fixed dose of either clozapine(300mg/d) or chlorpromazine(500mg/d) for 8 weeks in a randomized ,controlled design.The clinical symptoms were assessed using Brief Psychiatric Rating Scale (BPRS),Scale for Assessment of Negative Symptom(SANS),Scale for Assessment of Positive Symptom(SAPS),Wisconsin Card Sorting Test(WCST) at pre and post treatment.The serum Glu levels were measured at baseline and at the end of study.Results At baseline ,the serum Glu levels were significantly lower in the group with schizophrenia than in normal controls.After neuroleptic treatment,serum Glu levels were significantly increased in the clozapine treatment group(t= 5.86 ,P0.01),but not in the chlorpromazine treatment group. There was a positive correlation between the change of serum Glu levels and the clinical effectiveness in the clozapine treatment group(r=0.502,P0.01).Conclusion There may be some relevance between the clinical effectiveness of clozapine and the change of serum Glu levels.