1. Department of Psychology; Social Work and Public Health; Oxford Brookes University; Oxford; OX3 0FL; UK
2. Department of Community Health and Prevention; School of Public Health; Drexel University; Philadelphia; PA; USA
3. School of Social Work and Social Policy and Children's Research Centre; Trinity College Dublin; Dublin; Ireland
4. School of Psychology; Deakin University; Geelong; Vic.; Australia
5. Centre for Addiction Research; Faculty of Medical and Health Sciences; The University of Auckland; Auckland; New Zealand
6. Faculty of Health Sciences; Simon Fraser University; Burnaby; Canada
7. National Centre in HIV Social Research; Faculty of Arts and Social Sciences; The University of New South Wales; Sydney; NSW; Australia