[1] Univ Edinburgh, Dept Psychol, Edinburgh, Midlothian, Scotland
[2] Univ Dundee, Sch Psychol, Dundee DD1 4HN, Scotland
[3] Univ Aberdeen, Dept Mental Hlth, Aberdeen AB9 1FX, Scotland
[4] Univ Edinburgh, Dept Geriatr Med, Edinburgh, Midlothian, Scotland