ORIGINAL PAPER Violence and crime among male inpatients with severe mental illness: attempting to explain ethnic differences Matt Bruce • Deborah Cobb • Holly Clisby • David Ndegwa • Sheilagh Hodgins Received: 22 February 2013 / Accepted: 30 August 2013 / Published online: 17 September 2013 Ó European Union 2013 Abstract Background Studies report that in the UK, among men with severe mental illness (SMI), those of black Caribbean ethnicity display increased risk of aggressive behaviour, criminal convictions, and schizophrenia. The study aimed to compare aggressive behaviour and criminal convictions among men with SMI of white British, black Caribbean and black African ethnicity, and to explore factors asso- ciated with differences across ethnicities. Method Sample 1 included 1,104 male inpatients with SMI. Sample 2 included a representative sub-sample of 165 who completed interviews, and authorized access to med- ical and criminal files. Ethnicity was self-ascribed. Results Staff-rated violence prior to admission, self- reported aggressive behaviour, and convictions for non- violent and violent crimes differed among men with SMI of different ethnicities. Relative to men with SMI of white British ethnicity, those of black African ethnicity showed decreased risk of aggressive behaviour, and those of black Caribbean ethnicity showed elevated risk of convictions for non-violent, and marginally, for violent crimes. Relative to men with SMI of black African ethnicity, those of black Caribbean ethnicity showed elevated risk of aggressive behaviour and criminal convictions. Proportionately more of the men of both black African and black Caribbean ethnicity, than those of white British ethnicity, presented schizophrenia spectrum disorders. Multivariate analyses failed to identify factors that would explain differences in aggressive behaviour, and criminal convictions across ethnic groups. Conclusions Differences in four different measures of aggressive and antisocial behaviour among men with SMI of different ethnicities were observed but factors associated with these differences were not found. Keywords Ethnicity Á Violence Á Criminal convictions Á Schizophrenia Á Antisocial personality disorder Introduction Severe mental illness, ethnicity, aggressive behaviour, and criminality Investigations of large population cohorts have shown that non-violent and violent crime is elevated among persons with severe mental illness (SMI) defined to include schizophrenia, schizo-affective disorder, major depression, bipolar disorder, and other psychoses relative to the general population [17, 21]. Aggressive behaviour and violent crime by people with SMI increases stigma, limits access to treatment, reduces the likelihood of stable and satisfying relationships, and of employment. Such behaviour may lead to imprisonment, where intimidation and abuse of persons with psychoses are common. As part of a larger study examining comorbidity, vio- lence, and criminal behaviour among men with SMI we M. Bruce Á D. Ndegwa South London and Maudsley Trust, Forensic Services, London, UK M. Bruce (&) Á D. Cobb Á H. Clisby Á D. Ndegwa Á S. Hodgins Department of Forensic and Neurodevelopmental Science, Institute of Psychiatry, Kings College London, De Crespigny Park, Box P023, London SE5 8AF, UK e-mail: matt.bruce@kcl.ac.uk S. Hodgins De ´partement de Psychiatrie, Universite ´ de Montre ´al, Montreal, Canada 123 Soc Psychiatry Psychiatr Epidemiol (2014) 49:549–558 DOI 10.1007/s00127-013-0760-5