[1] Univ Oxford, Ctr Evidence Based Intervent, Dept Social Policy & Intervent, Oxford OX1 2ER, England
[2] Univ Cape Town, Groote Schuur Hosp, Dept Psychiat & Mental Hlth, Cape Town, South Africa
[3] Univ Witwatersrand, Fac Hlth Sci, Sch Clin Med, Johannesburg, South Africa
[4] Brown Univ, Sch Publ Hlth, Ctr Alcohol & Addict Studies, Dept Behav & Social Sci, Providence, RI 02912 USA
[5] Univ Oxford, Dept Int Dev, Oxford OX1 2JD, England
[6] UCL, Royal Free Hosp, Dept Infect & Populat Hlth, London WC1E 6BT, England