The effect of clozapine on aggressive behaviour in patients with chronic schizophrenia

We studied the effect of 12 months' treatment with clozapine (150-400 mg/day) in 16 chronic schizophrenic patients with aggressive behaviour. The number of aggressive episodes, the time spent in seclusion and physical restraint, and the number of pharmacological interventions used as chemical restraint during the 12 months of clozapine treatment were calculated and compared to those for the previous 12-month period (during which treatment was with conventional antipsychotics). During clozapine therapy there was a statistically significant decrease (P<0.001) in all the parameters of aggressive behaviour which we investigated, as compared with the pre-clozapine period. The reduction in aggressive behaviour was more prominent within the first 6 months of clozapine administration. Clozapine treatment was also associated with a global improvement in psychosis, as measured by the Brief Psychiatric Rating Scale. Despite the limitations in sample size and study design, our results confirm that clozapine appears more effective than classical antipsychotics in reducing aggressive behaviour in chronic schizophrenic patients.