Background: Prevalence of childhood trauma is elevated among individuals with severe mental illness (SMI) compared to the general population and associated with poor prognosis, substance misuse, lower treatment compliance and violence. Antisocial personality disorder (ASPD) typologies (childhood vs adult onset) also represent possible mediating mechanisms to explain risk of violence among men with SMI. The current study aimed to explore an explanatory pathway linking childhood traumatic exposure, antisocial personality typologies and risk of violent behaviour among adult male inpatients with SMI. Methods: A total of 162 male inpatients with SMI were examined using a cross-sectional survey design. Information was extracted from medical files, interviews and official criminal records. Results: Fifty-two participants (32.1%) reported experiencing a childhood trauma before 15. This group was 2.8 times more likely to engage in violent acts within the past 6 months than those without such a history. Furthermore, those with childhood onset ASPD (early starters) were more likely to report childhood trauma and engage in violence compared to adult onset ASPD (late starters) and those without antisocial histories. Multivariate analyses revealed that early starter ASPD was the only variable that independently predicted violence and mediated the relationship between childhood trauma and recent violent acts. Conclusions: A significant subset of men reporting trauma and antisocial conduct from childhood (early starter ASPD) is at considerably elevated risk of engaging in violent behaviours. Assessment of antisocial typologies in men with SMI may assist effective and defensible case prioritisation, resource allocation and treatment planning. (C) 2014 Elsevier B.V. All rights reserved.