Profiling Homicides Based on Impulsive or Proactive Natures in Male Schizophrenia Patients

The main aim of this study was to ascertain whether a relationship existed between the modus operandi and motivation of homicide, clinical characteristics, and psychopathic traits in schizophrenia. Forty-seven male homicide perpetrators with schizophrenia were included in the study. We classified types of homicide perpetrated by the patients as predominantly impulsive (n = 27) or proactive (n = 20) in nature. We also evaluated the psychotic motivation accompanying the homicide. Forty-four (93.6%) of the homicides were psychotically motivated. The victim was a stranger in only 8.5 percent of the homicides. Use of firearms as a killing method was significantly higher in predominantly proactive homicides (30%) compared with impulsive homicides (3.7%). Infidelity delusions were more frequent in proactive homicides than in impulsive homicides. According to regression models, a predominantly proactive homicide was significantly associated with being married, older age at illness onset, killing with firearms, infidelity delusions and a high PCL-R affective facet score in univariate analyses. Multivariate analyses showed a significant association with infidelity delusions and a high PCL-R affective facet score. Our results confirm that certain predispositions, as well as contextual factors, may be associated with the violent subtype of homicidal behavior in perpetrators with schizophrenia.