1. Mwanza Intervention Trials Unit, Mwanza, Tanzania
2. MRC International Statistics and Epidemiology Group, London School of Hygiene and Tropical Medicine, London, UK
3. National Institute for Medical Research, Mwanza, Tanzania
4. Mental Health, Alcohol, Substance Use and Tobacco Research Unit, South African Medical Research Council, Pretoria, South Africa
5. Department of Psychology, Rhodes University, Makhanda, South Africa
6. Department of Psychiatry, University of Stellenbosch, South Africa
7. Department of Psychology, University of Johannesburg, Johannesburg, South Africa
8. School of Public Health and Family Medicine, University of Cape Town, Cape Town, South Africa
9. School of Public Health, University of the Witwatersrand, Johannesburg, South Africa