Effect of clozapine on physical and verbal aggression

The hypothesis that clozapine reduced serious physically and verbally aggressive behavior of persons with schizophrenia whose symptoms did not respond to typical neuroleptic treatment was tested.

Incident reports of aggression and restraint of 75 such inpatients were reviewed for 3 months before clozapine treatment and for 6 months of clozapine treatment. BPRS scores were also examined. Twenty-eight patients with no incidents were removed from study.

There were significantly fewer incidents of physical aggression per month per patient on clozapine than before clozapine (mean +/- S.D. = 0.13 +/- 0.25 vs. 0.54 +/- 0.93; t = 3.4, df = 46, p < 0.002) and a similar decline in verbal aggression (0.21 +/- 0.31 vs. 0.73 +/- 0.83; t = 4.3, df = 46, p < 0.000). On clozapine, 49% (n = 23) of patients had fewer incidents of physical aggression, 36% (n = 17) showed no change and 15% (n = 7) showed more. Seventy percent (n = 33) of patients had fewer incidents of verbal aggression, 4% (n = 2) showed no change and 25% (n = 12) had more. During the 3 months before clozapine, 14 patients (30%) were restrained a total of 40 times. During the first 6 months of clozapine treatment, three patients (6%) were restrained a total of six times. There were significant decreases in BPRS hostility, positive, negative and psychosis scores.

Clozapine appears to reduce serious aggression among some patients.