How do adolescents behave in the Mediterranean in terms of substance use patterns and risk behaviours? The work of MedSPAD, the Mediterranean School Survey on Alcohol and other Drugs, attempts to answer this question. This publication, carried out within the framework of the Pompidou Group’s Mediterranean Network on Drugs and Addiction, also provides information on socio-economic and drug policies around the region. The extensive comparison reveals a heterogeneous situation.Then, in a fresh analysis, this book presents new data from 11 Mediterranean countries on school-age youths’ interactions with selected substances and behaviours. It features an examination of early-onset behaviours, perceived substance availability and the prevalence of alcohol, tobacco, high-risk cannabis and other drug use, along with – as a newly added highlight of the survey methodology developed for this study – gambling, gaming and social media habits. Conducting the survey itself constituted an innovative step in the collection of these data, requiring training of local personnel to implement valid and reliable survey methods in schools and further analysis. This is the first time such a dataset from different countries has been compiled and analysed in this way, providing unprecedented insight into the drugs and addiction situation among youths at a regional scale.