Abstract
BACKGROUND: Violence among released prisoners with psychosis is an important public health problem. It is unclear whether treatment in prison can influence criminal behaviour subsequent to release. AIMS: To investigate whether treatment in prison can delay time to reoffending. METHOD: Our sample consisted of 1717 adult prisoners in England and Wales convicted of a serious violent or sexual offence. We used Cox regression to investigate the effects of treatment received in prison on associations between mental illness and time to first reconviction following release. RESULTS: Prisoners with current symptoms of schizophrenia reoffended quicker following release. Nevertheless, treatment with medication significantly delayed time to violence (18% reduction). Treatment for substance dependence delayed violent and non-violent reoffending among prisoners with drug-induced psychosis. CONCLUSIONS: Identifying prisoners with psychosis and administering treatment in prison have important protective effects against reoffending. Repeated screening with improved accuracy in identification is necessary to prevent cases being missed. DECLARATION OF INTEREST: None. COPYRIGHT AND USAGE: © The Royal College of Psychiatrists 2015. This is an open access article distributed under the terms of the Creative Commons Non-Commercial, No Derivatives (CC BY-NC-ND) licence.