Polydrug use among adolescents: comparing knowledge of risk behavior vs policy drivers by processing ESPAD data with a network approach.

Despite global policies, alcohol and illicit drug use among adolescents continues to be a major public health issue. A large number of nationally representative samples suggests that a positive association exists between alcohol and/or tobacco use and consumption of other substances'. Polydrug abuse has been increasingly reported in emergency room admissions and in recent years the ways of consuming illicit substances are changed and the poly-use represents "normality" among frequent users. This study aims to identify user profiles based on substances used, in order to provide a basis for developing further drug policies. More evidence-based knowledge is needed to ascertain the best possible care for polydrug users and especially for problem drug users, as for example those with mental disorders. To study concurrently many risk behaviors, with new methods able to show "connections" among them and other subject characteristics, may represent the basis for future investigations and more targeted policies. Network analysis is suited to describing, exploring, and understanding structural and relational aspects of complex scenarios, as its application enables the examination of large data sets to identify complex relationships that may exist and go undetected either because of non-statistically significant observations, or simple lack of consideration of the potential for interactions. We believe that the network-based approach presented here, may represent a valid framework to handle heterogeneous data originating in different sources and highlight the relationships among them, since it is possible to represent different types of subjects and their connections within the same network.