1. British Columbia Centre on Substance Use, Vancouver, Canada.
2. CIHR Canadian HIV Trials Network, Vancouver, Canada.
3. Faculty of Arts and Social Sciences, School of Public Policy, Simon Fraser University, Vancouver, Canada.
4. Department of Medicine, St. Paul's Hospital, University of British Columbia, Vancouver, Canada.
5. Faculty of Health Sciences, Centre for Applied Research in Mental Health & Addiction, Simon Fraser University, Vancouver, Canada.