Abstract
Few studies have extensively studied the aggressive behaviours of mentally disordered offenders. This investigation compared 14 schizophrenics found not guilty of homicide by reason of insanity (NGRI) with 12 schizophrenics convicted of homicide. A comparison group of 15 homicide offenders with no major mental disorder was used. Drug and alcohol consumption, previous history of aggression against others as well as mental health were assessed using standardized, reliable, valid instruments. Significantly more of the inmates with no major mental disorder were diagnosed as having a history of drug or alcohol abuse or dependency (60%) than the NGRI schizophrenics (35.7%). In addition, both groups of convicted homicide offenders were more likely to have committed homicide under the influence of drugs or alcohol than the NGRI group. No significant difference distinguished the groups for the mean number of aggressive incidents. The subjects found NGRI assaulted more often during an acute phase of mental illness than the convicted schizophrenics. Although both groups appeared to have a similar number of hospitalizations, most of the hospitalizations of the convicted schizophrenics occurred after the crime.