The French figure among the largest consumers of cannabis in Europe, both according to general population surveys of adults from various European countries and the European School Survey Project on Alcohol and Other Drugs (ESPAD survey) carried out among more than 100,000 15-16 year old adolescents from most countries in Europe. Among the countries surveyed who have the most strict and suppressive policies concerning the use of psychotropic drugs, the level of consumption of cannabis appears particularly high in France and lowest in Sweden; although in a country diametrically opposed in terms of policy measures in this regard, The Netherlands (a country which carries the image of much freedom and leeway in this matter), actually occupies the position of average consumption rates in the middle of the two extreme cases aforementioned. Even more important than legislation is the presence of networks of close-knit relationships between young people; this is a critical aspect which has a strong influence in determining the choice whether or not to consume a product such as cannabis. In this manner, adolescents' behaviour and practices are integrally linked to the opinions, perceptions and use of his/her peers.