A psychologist, adult psychotherapist, family therapist and researcher, international expert in the field of dissociation and the treatment of trauma-related disorders. He is Emeritus Professor of Psychopathology of Chronic Traumatization at the Department of Clinical and Health Psychology at Utrecht University, the Netherlands. He was Chief of Research at the Cats-Polm Institute in Zeist – a research institute in the area of childhood abuse and neglect, and a lead psychotherapist at the Mental Health Center Buitenamstel in Amsterdam.

He has been on the Editorial Board of a number of scientific journals, and he has published several books in the area of trauma and dissociation, loss, and bereavement, and over 100 articles in peer-reviewed scientific journals. Prof. van der Hart is a Past-President of the International Society for Traumatic Stress Studies (ISTSS), a former Vice-President and Fellow of the International Society for the Study of Dissociation and Fellow of the American Society of Clinical Hypnosis (ASCH). He is a scholar in Pierre Janet studies.