[1] Univ New South Wales, Simpson Ctr Hlth Serv Res, South Western Sydney Clin Sch, Sydney, NSW 2170, Australia
[2] Ingham Inst Appl Med Res, Sydney, NSW, Australia
[3] Univ New South Wales, Sch Publ Hlth & Community Med, Sydney, NSW, Australia
[4] Univ Sydney, Fac Med, Susan Wakil Sch Nursing & Midwifery, Sydney, NSW, Australia
[5] Queensland Univ Technol, Sch Publ Hlth & Social Work, Brisbane, Qld, Australia
[6] Univ Western Australia, Fac Hlth & Med Sci, Div Emergency Med, Perth, WA, Australia
[7] Harry Perkins Inst Med Res, Ctr Clin Res Emergency Med, Perth, WA, Australia
[8] Royal Perth Hosp, Emergency Dept, Perth, WA, Australia
[9] New South Wales Hlth, Psychiat Res & Teaching Unit, Liverpool Hosp, Sydney, NSW, Australia
[10] Univ New South Wales, Fac Med, Sch Psychiat, Sydney, NSW, Australia
[11] Edith Cowan Univ, Sch Nursing & Midwifery, Perth, WA, Australia
[12] Univ New South Wales, Prince Wales Clin Sch, Sydney, NSW, Australia
[13] Prince Wales Hosp, Emergency Dept, Sydney, NSW, Australia
[14] Sir Charles Gairdner Hosp, Emergency Dept, Perth, WA, Australia