1. University of York; Department of Health Sciences; Seebohm Rowntree Building, Heslington York UK YO10 5DD
2. University of Cape Town; Department of Psychiatry and Mental Health; Cape Town South Africa
3. University of Stellenbosch; Interdisciplinary Health Sciences; Cape Town South Africa
4. Liverpool School of Tropical Medicine; Department of Clinical Sciences; Pembroke Place Liverpool UK L3 5QA
5. South African Medical Research Council; Health Systems Research Unit; PO Box 19070 Tygerberg Cape Town South Africa 7505
6. University of Cape Town; School of Public Health and Family Medicine; Rondebosch Cape Town South Africa 7700
7. Stellenbosch University; Department of Psychology; Private Bag X1 Matieland Western Cape South Africa 7602
8. South African Medical Research Council; Biostatistics Unit; Cape Town South Africa