Non-Criminal Justice Interventions for Countering Cognitive and Behavioural Radicalisation Amongst Children and Adolescents: A Systematic Review of Effectiveness and Implementation: A Systematic Review.

Growing numbers of young people are encountering the counter-terrorism system. This international trend raises important questions about the effectiveness of efforts to prevent and counter childhood and adolescent radicalisation. This review examines the effectiveness and implementation of interventions designed to counter cognitive and behavioural radicalisation amongst children and adolescents up to 19 years of age. It examines secondary and tertiary interventions working with at-risk and radicalised youth outside the criminal justice system. This focus reflects the growing recognition that diverting young people away from the criminal justice system helps mitigate the risks of securitisation, criminalisation, and stigmatisation. This review sought to answer three research questions: (1) Are secondary and tertiary interventions delivered outside of the criminal justice system effective at countering the cognitive and behavioural radicalisation of children and adolescents? (2) Are secondary and tertiary interventions delivered outside of the criminal justice system being implemented as intended? (3) What factors influence how interventions working with children and adolescents outside of the criminal justice system are implemented? Studies were identified through electronic searches of 20 academic and 50 grey literature sources; hand searches of academic journals and clinical trial repositories; forward and backward citation searches; and consultation with academic experts. Studies published after 2000 in English were eligible for inclusion. Searches of academic and grey literature sources were conducted in August and September 2024, respectively, with all remaining searches completed by December 2024. Studies had to report on secondary or tertiary interventions or prevention work outside of the criminal justice system (i.e., outside of correctional, custodial, or probation contexts) that sought to counter cognitive and behavioural radicalisation, often referred to as countering violent extremism (CVE) programming. Three types of interventions were included: (1) those designed for children and adolescents; (2) those working with children and adolescents as part of wider cohorts, provided a significant proportion of clients were aged 19 or under, or that provided insights specific to children and adolescents; or (3) those working with youth (or young people), broadly defined. Experimental or stronger quasi-experimental research designs were eligible for inclusion in the assessment of effectiveness (Objective I). Inclusion criteria for the assessment of implementation (Objective II) and of implementation factors (Objective III) were broader, and included non-experimental quantitative designs and qualitative research. The corpus of evidence was screened by trained reviewers, guided by screening tools, across a title/abstract and full-text screening phase. Data were extracted using a piloted tool to capture key information on each included study. Risk of bias information was extracted using relevant existing tools. Effectiveness data from a single study was converted into a standardised effect size. Data relating to implementation was coded through a process of inductive and deductive coding. Twenty-nine studies were included in the review. Only one quasi-experimental study was eligible for inclusion in the analysis of effectiveness (Objective I). In this study, Kolbe (2019) reported that at-risk young people participating in a group-based intervention who also received individualised home-based support were less likely to join a violent extremist group than young people who only participated in the group-based intervention (Chi-square: 5.295,