[1] Univ Strathclyde, Sch Psychol Sci & Hlth, 40 George St, Glasgow G1 1QE, Lanark, Scotland
[2] Heriot Watt Univ, Dept Psychol, Edinburgh, Midlothian, Scotland
[3] Heriot Watt Univ, Ctr Appl Behav Sci, Edinburgh, Midlothian, Scotland
[4] Johns Hopkins Med Inst, Ctr Aging & Hlth, Baltimore, MD 21205 USA
[5] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Epidemiol, Baltimore, MD USA
[6] Johns Hopkins Bloomberg Sch Publ Hlth, Dept Mental Hlth, Baltimore, MD USA