Clozapine effect on the negative symptoms of treatment-resistant schizophrenia

Abstract EN

Background : Conventional antipsychotics have unsatisfactory effects on treatment-resistant schizophrenia, but their effects on negative symptoms are unsatisfactory.

Since clozapine as an atypical antipsychotic is reported to be effective on the negative symptoms of this disorder, the author decided to carry out this study on a sample of resistant schizophrenics. Method : 74 schizophrenic patients considered as treatment-resistant by their psychiatrists, and were entered the research procedures.

To make sure about treatment-resistance, they were treated for six weeks with haloperidol and biperiden.

Then another BPRS was performed for them.

The patients with 20% or more decrease in BPRS total score, or an endpoint score less than 45, were excluded from research and then 62 patients were remained.

Finally 39 of them were selected according to sampling measures.

These patients were treated with clozapine for 21 weeks.

They were evaluated weekly by BPRS.

In addition to descriptive statistics, the data were analyzed by t-test (in correlated groups) and spearman coefficient of correlation. Results : The difference between the mean of negative scores in baseline and the fifth week of treatment with clozapine was statistically significant (t = 2.86, df = 38, p < 0.005).

The same rate was true for the baseline and other weeks of treatment.

The significant effect of clozapine on positive symptoms began since third week.

The means of negative symptoms scores from 5th week on ward gradually improved, but there was no significant difference between scores of any two weeks. Conclusion : A) Clozapine has significant therapeutic effect on negative symptoms of schizophrenia B) The significant therapeutic effect of clozapine on negative symptoms occurs early in treatment (5th week).

C) Amongst the negative symptoms, cIozapine has its highest effect on social isolation and withdrawal.