Recent research into schizophrenia has focused on some of the cognitive deficits associated with the condition which can have a greater impact on everyday activities than psychotic symptoms and have also been associated with violence. Some studies have suggested that second-generation antipsychotics are more effective at tackling cognitive deficits than earlier drugs while others have reported no advantage. Researchers in the U.S. studied 100 physically-aggressive inpatients with schizophrenia. A third were given clozapine, a third olanzapine and a third haloperidol. Olanzapine was much more effective at reducing participants' cognitive problems. In participants taking olanzapine - but not the two other drugs - improvements in cognition were associated with a reduction in violence. Clozapine was also found to markedly reduce violence but without improving participants' cognition.
Krakowski, Menachem I., Czobor, Pal and Nolan , Karen A. - Atypical antipsychotics, neurocognitive deficits, and aggression in schizophrenic patients. Journal of Clinical Psychopharmacology October 2008, 28(5), 485-493