According to the ‘Global burden of disease, injuries and risk factors study’ 2013 (Forouzanfar et al., 2015), tobacco and alcohol use are among the leading risk factors worldwide for premature death and morbidity, expressed in terms of disability-adjusted life years (DALYs). In Europe, of the 78 risk factors investigated, tobacco ranks second and alcohol fifth in terms of DALYs. Although not being a major risk factor, illicit drug use also contributes significantly (rank 22) to the global burden of years of life lost and years lived with disability. Substance-related harms to the users and to others and public health and safety concerns are the main reasons for the worldwide monitoring of such behaviours. Due to age restrictions on access to tobacco and alcohol, as well as the drug control measures covering illicit psychoactive substances, in most countries there is a particular emphasis on monitoring consumption among youths and adolescents. For instance, surveys on substance use among adolescents have a long tradition in Sweden (Swedish school surveys on substance use), England (‘Smoking, drinking and drug use among young people in England’), Germany (‘Drug affinity study’) and the United States (‘Monitoring the future’ study) and were implemented as early as 1970. With the initiation of the European School Survey Project on Alcohol and Other Drugs (ESPAD) in 1995, Europe created an instrument that enables comparisons between participating countries, due to a common methodology. After six waves of data collection over the past 20 years and the expansion of the European Union to now include 28 countries, the ESPAD survey also allows the analysis of temporal trends in over 40 countries, including 24 Member States of the European Union.

In the last few years, evidence has accumulated that behaviours such as internet use, gaming and gambling have the same potential to become addictive as psychoactive substances. However, while gambling has been included in the revised DSM-5 chapter ‘Substance-related and addictive disorders’, there is still no consensus for classifying excessive internet use and gaming as addictive behaviours (Regier et al., 2013). Independently of how these behaviours are treated by the international classification systems, extensive internet use, gaming or gambling in adolescents has long raised public concerns. This led the ESPAD researchers to extend the scope of the survey. In addition, new psychoactive substances, which are a public health and safety problem and have been monitored since the late 2000s, received special attention in the 2015 survey.