1 Benedikt Fischer and Jürgen Rehm are with the Institute for Mental Health Policy Research, Centre for Addiction and Mental Health, University of Toronto, Toronto, Canada. Wim van den Brink is with the Amsterdam Institute for Addiction Research, University of Amsterdam, Amsterdam, Netherlands. Bernard Le Foll is with the Translational Addiction Research Laboratory, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health, Toronto, Canada. Wayne Hall is with the Centre for Youth Substance Abuse Research, Faculty of Health and Behavioural Sciences, University of Queensland, Brisbane, Australia. Robin Room is with the Centre for Alcohol Policy Research, La Trobe University, Melbourne, Australia.