[1] Univ Manchester, Div Psychol & Mental Hlth, Jean McFarlane Bldg,Oxford Rd, Manchester M13 9PL, Lancs, England
[2] Royal Blackburn Hosp, Blackburn, Lancs, England
[3] Royal Blackburn Hosp, Intens Care & Anaesthesia, Blackburn, Lancs, England
[4] Keele Univ, Res Inst, Primary Care Res, Primary Care & Hlth Sci, Keele, Staffs, England
[5] Univ Cent Lancashire, Sch Med, Preston, Lancs, England