All participants were born in 1936 and had taken part in the Scottish Mental Survey of 1947; they were tested on psychological (including mood) and medical traits at about 70 years of age at the Wellcome Trust Clinical Research Facility (Western General Hospital, Edinburgh) and completed some questionnaires (including personality) at home [18]. The sample was Caucasian and lived independently in the Lothian region (Edinburgh city and surrounding area) of Scotland. Further description about participant recruitment can be found elsewhere [18]. DNA samples and psychological distress data were available for 1 078 participants. The available personality data gave an analysis sample of N = 951 for these traits of 470 men and 481 women. The mean age of the sample was 69.5 years (SD = 0.8). The mood states of anxiety and depression were assessed using the Hospital Anxiety Depression Scale (HADS) [19]. The personality traits of the Five Factor model (see Introduction) were measured using the NEO Five-Factor Inventory [20]. The NEO Five-Factor Inventory (NEO-FFI) is a 60-item inventory consisting of 12 items for each of the five factors.
