[1] Univ Edinburgh, Ctr Cognit Ageing & Cognit Epidemiol, Edinburgh, Midlothian, Scotland
[2] Northumbria Univ, Dept Psychol, Newcastle Upon Tyne NE1 8ST, Tyne & Wear, England
[3] Royal Coll Surg Scotland, Edinburgh, Midlothian, Scotland
[4] Univ Edinburgh, Student Counselling Serv, Edinburgh, Midlothian, Scotland