[1] Kings Coll London, Inst Psychiat Psychol & Neurosci, Natl Addict Ctr, London, England
[2] Kings Coll London, Inst Psychiat Psychol & Neurosci, Dept Biostat & Hlth Informat, London, England
[3] Whipps Cross Univ Hosp, Barts Hlth NHS Trust, London, England
[4] UCL, Inst Epidemiol & Hlth Care, London, England
[5] Global Drug Survey, London, England
[6] RMIT Univ, Social & Global Studies Ctr, Melbourne, Australia
[7] RMIT Univ, Digital Ethnog Res Ctr, Melbourne, Australia
[8] UNSW Sydney, Natl Drug & Alcohol Res Ctr, Randwick, Australia
[9] Univ Queensland, Fac Med, Ctr Hlth Serv Res, Brisbane, Australia
[10] Oxford Brookes Univ, Fac Hlth & Life Sci, Ctr Psychol Res, Oxford, England