Trauma, post-traumatic stress disorder and violence in the prison population: prospective cohort study of sentenced male prisoners in the UK

BACKGROUND: Violence is a common problem in prisons. Post-traumatic stress disorder (PTSD), a prevalent disorder in prison populations, has been identified as a risk factor for violent behaviour in community and military populations. Although cross-sectional associations between PTSD and prison violence have been documented, prospective cohort studies are required. AIMS: To investigate whether PTSD is an independent risk factor for prison violence, and examine the potential role of PTSD symptoms and other trauma sequelae on the pathway from trauma exposure to violent behaviour in prison. METHOD: A prospective cohort study was conducted in a large, medium security prison in London, UK. A random sample of sentenced prisoners arriving into custody (N = 223) took part in a clinical research interview, which assessed trauma histories, mental disorders including PTSD, and other potential sequelae of trauma (anger, emotion dysregulation). Incidents of violent behaviour were measured with prison records covering the 3 months after reception into custody. Stepped binary logistic regression and a series of binary mediation models were performed. RESULTS: Prisoners who met current (past month) criteria for PTSD were more likely to engage in violent behaviour during the first 3 months of imprisonment, after adjusting for other independent risk factors. The relationship between lifetime exposure to interpersonal trauma and violent behaviour in custody was mediated by total PTSD symptom severity. Hyperarousal and negatively valenced cognitive and emotional appraisal symptoms were particularly implicated in this pathway. CONCLUSIONS: The identification and treatment of PTSD has the potential to reduce violence in prison populations.