[1] Univ Manchester, Ctr Suicide Prevent, Ctr Mental Hlth & Risk, Manchester M13 9PL, Lancs, England
[2] Univ Bristol, Sch Social & Community Med, Bristol, Avon, England
[3] Univ Oxford, Warneford Hosp, Dept Psychiat, Ctr Suicide Res, Oxford, England
[4] Univ Manchester, Ctr Biostat, Inst Populat Hlth, Manchester M13 9PL, Lancs, England