School-based secondary prevention programmes for preventing violence

BACKGROUND: Early aggressive behaviour is a risk factor for later violence and criminal behaviour. Despite over 20 years of violence prevention interventions being delivered in the school setting, questions remain regarding the effectiveness of different interventions for children exhibiting aggressive behaviour. OBJECTIVES: To examine the effect of school based violence prevention programmes for children identified as aggressive or at risk of being aggressive. SEARCH STRATEGY: We searched CENTRAL, Cochrane Injuries Group specialised register, MEDLINE, EMBASE, other specialised databases and reference lists of articles. We also contacted authors and organisations to identify any further studies. SELECTION CRITERIA: We included trials meeting the following criteria; 1) participants were randomly assigned to intervention and control groups; 2) outcome data were collected concurrently; 3) participants comprised children in mandatory education identified as exhibiting, or at risk of, aggressive behaviour; 4) interventions designed to reduce aggression, violence, bullying, conflict or anger; 5) school based interventions; 6) outcomes included aggressive behaviour, school and agency responses to acts of aggression, or violent injuries. DATA COLLECTION AND ANALYSIS: Data were collected on design, participants, interventions, outcomes and indicators of study quality. Results of any intervention to no intervention were compared immediately post-intervention and at 12 months using meta-analysis where appropriate. MAIN RESULTS: Of 56 trials identified, none reported data on violent injuries. Aggressive behaviour was significantly reduced in intervention groups compared to no intervention groups immediately post intervention in 34 trials with data, (Standardised Mean Difference (SMD) = -0.41; 95% confidence interval (CI) -0.56 to -0.26). This effect was maintained in the seven studies reporting 12 month follow-up (SMD = -0.40, (95% CI -0.73 to -0.06)). School or agency disciplinary actions in response to aggressive behaviour were reduced in intervention groups for nine trials with data, SMD = -0.48; 95% CI -1.16 to 0.19, although this difference may have been due to chance and was not maintained, based on two studies reporting follow-up to two to four months (SMD = 0.03; 95% CI -0.42 to 0.47). Subgroup analyses suggested that interventions designed to improve relationship or social skills may be more effective than interventions designed to teach skills of non-response to provocative situations, but that benefits were similar when delivered to children in primary versus secondary school, and to groups of mixed sex versus boys alone. AUTHORS' CONCLUSIONS: School-based secondary prevention programmes to reduce aggressive behaviour appear to produce improvements in behaviour greater than would have been expected by chance. Benefits can be achieved in both primary and secondary school age groups and in both mixed sex groups and boys-only groups. Further research is required to establish whether such programmes reduce the incidence of violent injuries or if the benefits identified can be maintained beyond 12 months.