1 Department Internal Medicine 1 (Gastroenterology, Hepatology, Oncology, Infectious Diseases), Klinikum Saarbrücken, Saarbrücken, Germany.
2 Department Psychosomatic Medicine and Psychotherapy, Technische Universität München, Munich, Germany.
3 The National Hospital for Neurology and Neurosurgery, University College London Hospitals Foundation Trust, London, United Kingdom.
4 Department of Urology and Sexology, Medical Centre Leeuwarden, the Netherlands.
5 Departments of Anesthesiology/Division of Pain Medicine, Neurology and Psychology, University of Alabama at Birmingham, Birmingham, AL, United States.