1. Social and Epidemiological Research Department; Centre for Addition and Mental Health; London Ontario Canada
2. Psychology Department; Western University; London Ontario Canada
3. National Drug Research Institute; Curtin University; Perth Western Australia Australia
4. Dalla Lana School of Public Health; University of Toronto; Toronto Ontario Canada
5. Department of Sociology; Pennsylvania State University; State College Pennsylvania
6. Department of Psychology; Wayne State University; Detroit Michigan
7. Department of Epidemiology and Biostatistics; Western University; London Ontario Canada