1. Department of Mental Health, University of Aberdeen, Aberdeen, UK
2. School of Psychology, University of Aberdeen, Aberdeen, UK
3. Royal Cornhill Hospital, Aberdeen, UK
4. Centre for Health Quality, Outcomes and Economic Research, Edith Nourse Rogers Memorial Veterans Hospital, Bedford, MA
5. Boston University School of Public Health, Boston, , USA
6. Department of General Practice and Primary Care, University of Aberdeen, Aberdeen, UK
7. School of Health Sciences, Faculty of Health and Social Care, The Robert Gordon University, Aberdeen, UK