Clozapine is more effective than olanzapine or haloperidol at reducing aggression in patients with schizophrenia and conduct disorder, according to a study appearing in AJP in Advance.
The study by Menahem Krakowski, M.D., Ph.D., of the Nathan Kline Institute for Psychiatric Research in Orangeburg, N.Y., and colleagues examined data from 99 hospitalized schizophrenia patients aged 18 to 60. For the 12-week, double-blind clinical trial, the patients were randomly assigned to receive clozapine, olanzapine, or haloperidol to see which drug was associated with the greatest reduction in aggression. All participants had at least one clearly documented instance of verbal or physical aggression.
Based on clinical interviews and a review of the patients’ medical charts, the investigators diagnosed 53 of these patients with conduct disorder. The patients with or without conduct disorder were similar in many demographic and clinical factors, but those with conduct disorder had a longer duration of schizophrenia, were more likely to have a substance use disorder, and had fewer negative symptoms.
During the 12-week study, the patients with conduct disorder were more likely to exhibit aggression than those without, as assessed by the Modified Overt Aggression Scale (MOAS). This scale quantifies the number and severity of incidents involving verbal aggression, physical aggression against other people, and physical aggression against objects. Average MOAS scores at the end of the study were 42.6 for patients with conduct disorder and 22.1 for patients without. There were significant differences in medication groups, however: Among patients with conduct disorder, average MOAS scores were 71.6 in the haloperidol group, 40.7 in the olanzapine group, and 26.6 in the clozapine group. The average MOAS scores for patients with no conduct disorder who received haloperidol, olanzapine, and clozapine were 28.7, 24.9, and 15.0.
Krakowski and colleagues found that patients with schizophrenia and conduct disorder taking clozapine were three times as likely to exhibit less overall aggression and four times as likely to exhibit less physical aggression than those taking haloperidol. They noted that changes in both positive and negative schizophrenia symptom scores were similar among the patients during the study; thus, the improvements in aggression were likely not related to overall antipsychotic effects.
“The findings point to the superiority of clozapine, and to a lesser extent olanzapine, for these patients and have important implications for treatment,” the researchers wrote. “It is imperative to obtain a good history of conduct disorder, for if it is present, clinicians should consider clozapine as the primary drug for treatment.”
For related information, see the Psychiatric News article “Study Provides More Insight Into Association Between Schizophrenia, Violence.”
(Image: iStock/nathaphat)
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