Riadh Abed is a retired Consultant Psychiatrist, Medical Director, and Honorary Senior Clinical Lecturer at the University of Sheffield. He is currently working for the Mental Health Tribunal Service in England. He is a former (founding) Chair of the Evolutionary Psychiatry Special Interest Group at the Royal College of Psychiatrists and is currently its Finance Officer. He is also Secretary of the Section of Evolutionary Psychiatry at the World Psychiatric Association. He has been interested in the application of evolutionary theory to the understanding of mental disorder and has published novel evolutionary theories on eating disorders, OCD and schizophrenia.

Paul St John-Smith is a retired Consultant Psychiatrist, who has worked as an in-patient and community consultant as well as in dual diagnosis in the NHS. He is currently Chair of the Evolutionary Psychiatry Special Interest Group at the Royal College of Psychiatrists. He has had interests in adult general psychiatry, psychopharmacology, evidence-based medicine, substance abuse and application of evolutionary theory to the understanding of mental disorder.