Kitchen knives and homicide by mentally disordered offenders: A systematic analysis of homicide inquiries in England 1994–2010

There is a lack of data on kitchen knife use, in contrast to generic sharp instruments, in homicide. This systematic study sought evidence of a link between kitchen knife use and unplanned homicide by people with mental disorders. Independent homicide inquiries in England from 1994 to 2010 were analysed. In total, 69 cases were identified with complete data (n = 107); no significant differences were found between the samples with and without available knife data. Kitchen knives were used more frequently than other knives in homicides by users of mental health services, and there was an association with unplanned homicide. Schizophrenia or the presence of mental illness independently did not have a significant effect on the type of knife used. We found evidence against the stereotype of unusual weapons being used by mentally disordered homicide perpetrators and recommend further research into the control of access to kitchen knives to patients with mental disorders.