[1] Univ Liverpool, Sch Populat Community & Behav Sci, Child Mental Hlth Unit, Alder Hey Childrens NHS Fdn Trust, Liverpool L12 2AP, Merseyside, England
[2] Human Dev Res Fdn, Islamabad, Pakistan
[3] Univ Sheffield, Sch Med & Biomed Sci, Sheffield, S Yorkshire, England
[4] Univ Manchester, Dept Epidemiol & Biostat, Manchester, Lancs, England
[5] Univ Manchester, Sch Med, Psychiat Res Grp, Manchester, Lancs, England