Clozapine, olanzapine, or haloperidol reduced assaults in 99 individuals with schizophrenia and assaultive behaviors.

BACKGROUND: Violence in schizophrenia poses a major clinical and public health challenge. This study examined how core psychopathological features, conduct disorder (CD), and pharmacological treatment influence violent behavior by looking at the interaction among these variables. We also investigated the clinical differences between CD and non-CD patients. METHODS: 99 individuals with schizophrenia and with assaultive behaviors were randomly assigned in a double-blind design to clozapine, olanzapine, or haloperidol. Participants were further classified by presence or absence of CD. Clinical evaluation included the Positive, Excitement, and Depression factors of the Positive and Negative Syndrome Scale (PANSS), the Buss-Perry Aggression Questionnaire (BPAQ), and Barratt Impulsiveness Scale. RESULTS: Individuals with CD displayed higher trait aggression on the BPAQ and elevated endpoint PANSS Excitement, Hostility, and Anger scores compared with non-CD participants. Reductions in assaults were related to improvements in psychopathological measures in both the CD and non-CD groups, though these associations were stronger among non-CD participants. The relationship between symptom improvement and reduced aggression also varied by medication: in the haloperidol group, aggression reduction was closely associated with symptom improvement; in the clozapine group, no such association was found, suggesting a strong and direct anti-aggressive effect independent of symptom improvement; olanzapine showed an intermediate pattern. CONCLUSION: These findings highlight the importance of interactions among symptoms, conduct disorder, and medication in determining violence. They also point to the multifactorial etiology of violence in patients with schizophrenia and to the need for tailored treatment strategies to effectively reduce violence, especially in high-risk population.