1. Program Evaluation Unit, Centre for Health Program Evaluation, School of Population Health, The University of Melbourne, P O box 477, West Heidelberg, Victoria, Australia
2. Mental Health Research Institute, Victoria, Australia
3. Mental Health Research Institute, 155 Oak Street, Parkville, Victoria, 3053, Australia
4. Department of Psychological Medicine, Faculty of Medicine, Monash University, Victoria, Australia
5. Department of Psychiatry, Faculty of Medicine, The University of Melbourne, Victoria, Australia
6. School of health Sciences, Faculty of Health and Behavioural Sciences, Deakin University, Victoria, Australia