This document constitutes the Institute's formal guidance on community-based interventions to reduce substance misuse among vulnerable and disadvantaged children and young people. The recommendations in this section are presented without any reference to evidence statements. Appendix A in the original guideline document repeats the recommendations and lists their linked evidence statements. Community-based interventions are defined as interventions or small-scale programmes delivered in community settings, such as schools and youth services. They aim to change the risks factors for the target population. For the purposes of this guidance, substance misuse is defined as intoxication by – or regular excessive consumption of and/or dependence on psychoactive substances, leading to social, psychological, physical or legal problems. It includes problematic use of both legal and illegal drugs (including alcohol when used in combination with other substances).