Homicide offenders including mass murder and infanticide 

There is a widespread public perception of the mentally ill as violent. Until the early 1980s there was a consensus view that patients with severe mental illness were no more likely to be violent than the general population. Emerging evidence from various countries over the past two decades, however, has established a small, yet significant, association between mental illness and violence. There are 500–600 homicides annually in England and Wales. Perpetrators and victims are predominantly young males, especially when the victim is unknown to the perpetrator. In such ‘stranger homicides’ perpetrators are less likely to have a lifetime history of mental illness, symptoms of mental illness at the time of the offence, or contact with mental health services. Despite an increasing rate of homicides in the general population, convictions for infanticide and the rate of infant homicide has remained relatively constant, at around 4.5 per 100 000 live births. Infanticide has become a generic term for killing of infants, even though the criminal charge in England applies to a crime for which only a woman can be indicted. Multiple homicides, in particular serial homicides, have generated a great deal of public and media interest over recent decades yet this phenomenon is rare in the UK. The rarity of these events means that there is a lack of empirical evidence about the characteristics of perpetrators and victims in the UK, with most evidence emanating from the United States. Even then, however, there is an absence of systematic, robust evidence, with many studies being limited by small sample size. Around 1 in 10 perpetrators of homicide in England and Wales are female, which is consistent with data from other countries. Stranger homicide by females is rare. In one-quarter of cases the victims are the perpetrators’ own children and a current or former partner in over a third. Homicides perpetrated by the elderly are exceptionally rare. There is a well documented increased risk of violence in those with schizophrenia. The aim of the National Confidential Inquiry is to collect detailed clinical information on people convicted of homicide, focusing on those with a history of contact with mental health services. Nearly one in three Inquiry cases were seen during the week before the homicide, a similar proportion within 1–4 weeks and the remainder between 1–12 months. A substantial proportion had mental state abnormalities at final contact, often distress, depressive symptoms, hostility, or increased use of alcohol or drugs. Despite this immediate risk was judged to be low or absent in 88 per cent cases at the last contact.