[1] Univ New S Wales, NHMRC Ctr Res Excellence Mental Hlth & Subst Use, Natl Drug & Alcohol Res Ctr, Sydney, NSW, Australia
[2] Univ Bristol, Sch Social & Community Med, Bristol, Avon, England
[3] Virginia Commonwealth Univ, Virginia Inst Psychiat & Behav Genet, Richmond, VA USA
[4] London Sch Hyg & Trop Med, Dept Populat Hlth, London WC1, England