This systemic review investigates the current evidence for the effectiveness of anger and/or aggression interventions for people with intellectual disabilities (ID) in receipt of forensic mental health services. Due to the prevalence within
this population of difficulties with anger and aggression, and the associated substantial individual and societal consequences, the provision of psychological interventions has become increasingly common. However, no critical synthesis of the empirical evidence relating to their effectiveness has previously been conducted. Sixteen peerreviewed controlled trials or case series designs published between 2001 and 2016 met the inclusion criteria. The results highlight an emerging evidence base for the use of CBT in improving anger regulation, and for a range of psychological therapies in reducing aggressive behaviour. However, consistent methodological shortcomings limit the
generalisability of findings and currently preclude firm conclusions on effectiveness. Recommendations are made for future research to address these shortcomings, including clearly-defined adaptations, adequately powered sample sizes, carefully designed baselines and follow-up periods. Despite the current status of evidence, the review provides an accessible and objective foundation to inform decision-making by service commissioners and clinicians providing anger and aggression interventions to people with ID.