1. Department of Alcohol, Drugs, and Addiction; National Institute for Health and Welfare; Helsinki; Finland
2. Division of Forensic Medicine and Drug Abuse Research; Norwegian Institute of Public Health; Oslo; Norway
3. School of Medicine, Department of Molecular Medicine, Forensic Toxicology and Antidoping; University of Padova; Padova; Italy
4. Department of Lifestyle and Participation; National Institute for Health and Welfare; Helsinki; Finland
5. Department of Clinical Chemistry, Microbiology and Immunology; Ghent University and Laboratory of Clinical Biology, Ghent University Hospital; Ghent; Belgium