Characteristics of domestic homicide perpetrated by persons with severe mental illness - a forensic psychiatry observation population-based study

Background: Domestic homicide (killing of a person aged 16 or older by a family member or a current or former partner) accounts for 50% - 70% of homicides perpetrated by offenders with mental illness. Despite these statistics, surprisingly little is currently known about the characteristics of domestic homicides perpetrated by those with severe mental illness. To the best of our knowledge, domestic homicide in the context of severe mental illness has not been researched in South Africa. Objective: To investigate domestic homicides by offenders with severe mental illness referred to the Forensic Mental Health Service at Valkenberg Hospital for forensic psychiatric observation. Methods: A five-year retrospective folder review was conducted to obtain data on the characteristics of offenders and victims, as well as the circumstances surrounding the homicide. Results: The majority of the offenders in our sample were young (mean age of 31), single, unemployed males who were known to mental health care services. Substance use disorders and non-adherence to medication were common. Psychotic disorders were the most prevalent diagnoses. The majority of victims were male and a significant minority of the domestic homicides were parricides (28.6%). The incident took place at the victim's residence or the victim and perpetrator's shared residence in most cases. Stabbing was the most common method used. Almost half of the perpetrators were psychotic when the incident took place and 60% of these were first episode psychoses. In spite of the high prevalence of substance use disorders (66.7%), only 23.8% of the sample reported that they were intoxicated when they committed the offence. Conclusions: The majority of our sample was known to mental health care services. This implies that there were potential missed opportunities to prevent these lethal assaults. Our research identified treatment adherence, comorbid substance use disorders and aggressive treatment of first episode psychosis as a possible focus of future interventions in order to prevent domestic homicides due to mental illness