[1] Cardiff Univ, Sch Med, Neuadd Meirionydd, Cardiff CF14 4XN, Wales
[2] La Trobe Univ, Australian Inst Primary Care, Cochrane Consumers & Commun Review Grp, Bundoora, Vic 3086, Australia
[3] Llandough Hosp, Clin Effectiveness Support Unit Wales Roseway, Penarth, S Glam, Wales
[4] Univ Sydney, Sch Psychol, Sydney, NSW 2006, Australia