How can we ensure that a public health intervention is effective? What key principles must be implemented to ensure that a program has a positive impact on populations? This special report aims to provide a collection of concise answers to these critical questions. It focuses on the issue of substance use disorders (tobacco, cannabis, alcohol, etc.) among young people. Some fifteen experts contributed to this overview of current knowledge—and practices—regarding “evidence-based interventions,” including examples of evaluated programs, while highlighting both their strengths and weaknesses.