Director of the Center for the Study of Violence at Harvard Medical School and former medical director of the Bridgewater State Hospital for the criminally insane, Dr. Gilligan was brought in as Director of Mental Health for the Massachusetts prison system because of the high suicide and murder rates within their prisons. When he left 10 years later, the rates of both had dropped to virtually zero.

His therapeutic, diagnostic and forensic work with violent individuals, including addressing prison riots, hostage-taking incidents, hunger strikes, terrorism, gang rapes, prison suicides and homicides, have taken place in maximum-security prisons and mental hospitals throughout the United States, Canada and the United Kingdom.

Current research projects include an evaluation of an experimental violence prevention programme in the jails of San Francisco for the Soros Foundation. His publications include Violence: Our Deadly Epidemic and Its Causes (Grosset/Putnam, New York, 1996); Violence: Reflections on Our Deadliest Epidemic (London: Jessica Kingsley, 1999) and Preventing Violence: An Agenda for the Coming Century (London and New York: Thames and Hudson).