1. Karolinska Institutet, Department of Public Health Science, Stockholm, Sweden
2. Karolinska Institutet, Department of Public Health Science, Stockholm, Sweden Centre for Epidemiology and Community Medicine, Stockholm, Sweden
3. Karolinska Institutet, Department of Public Health Science, Stockholm, Sweden Stockholm University, Centre for Social Research on Alcohol and Drugs, Stockholm, Sweden
4. The Swedish Council for Information on Alcohol and Other Drugs, Stockholm, Sweden European Monitoring Centre for Drugs and Drug Addiction, Lisbon, Portugal