John Marsden is a chartered pschologist and senior lecturer in addictive behaviour at London's Institute of Psychiatry and a senior member of the National Addiction Centre. He has coordiinated substance-misuse research projects for government departments and international agencies. He is an expert consultant to the UK Anti-Drugs Coordiinating Unit, the World Health Organisation and the United Nations Drug Control Programme. He trained in psychology at University College London 1981-1984 and his PhD studies were on the treatment of alcohol and other drug problems. From 1987-1994 he was a member of the central management team for Turning Point, the UK's "largest voluntary agency in the field of drugs, alcool and mental health".