1. Brighton and Sussex Medical School; Division of Primary Care and Public Health; Mayfield House; Brighton; UK
2. Guy's and St Thomas' Hospitals NHS Trust, Department of Oral and Maxillofacial Surgery; Guy's Hospital; London; UK
3. Institute of Psychiatry, Department of Psychology; King's College London, Guy's Hospital; London; UK
4. Brighton and Sussex University Hospitals NHS Trust, Department of Oral and Maxillofacial Surgery; The Royal Sussex County Hospital; Brighton; UK