1. University of Cape Town; Department of Psychiatry and Mental Health, Faculty of Health Sciences; Cape Town South Africa
2. University of Copenhagen; Department of Mathematics, Faculty of Science; Universitetsparken 5 Copenhagen Ø Denmark 2100
3. University of Birmingham; Public Health, Epidemiology and Biostatistics; Edgbaston Birmingham UK B15 2TT
4. Stellenbosch University; Centre for Evidence-based Health Care; PO Box 19063 Tygerberg Cape Town South Africa 7505
5. South African Medical Research Council; South African Cochrane Centre; PO Box 19070 Tygerberg Cape Town Western Cape South Africa 7505