[1] Univ Manchester, Wythenshawe Hosp, Educ & Res Ctr, Dept Med Stat, Manchester M23 9LT, Lancs, England
[2] Wythenshawe Hosp, Dept Clin Psychol, Manchester M23 9LT, Lancs, England
[3] Univ Manchester, Div Psychiat, Manchester M13 9PL, Lancs, England
[4] Univ Manchester, Dept Clin Psychol, Manchester M13 9PL, Lancs, England
[5] Univ Manchester, Dept Geriatr Med, Manchester M13 9PL, Lancs, England
[6] Inst Psychiat, Dept Mental Hlth & Aging, London, England
[7] NW Wales Natl Hlth Serv Trust, Dept Orthopaed, Bangor, Gwynedd, Wales