A collective trauma is a traumatic psychological effect shared by a group of people of any size, up to and including an entire society. Traumatic events witnessed by an entire society can stir up collective sentiment, often resulting in a shift in that society's culture and mass actions. Well known collective traumas include: The Holocaust, the Armenian Genocide, Slavery in the United States, the Atomic bombings of Hiroshima and Nagasaki, the Trail of Tears,, the Attack on Pearl Harbor, the MS Estonia in Sweden, the September 11, 2001 attacks in the United States, the Halabja chemical attack and various others. Collective traumas have been shown to play a key role in group identity formation. During World War II, a US submarine, the USS Puffer, came under several hours of depth charge attack by a Japanese surface vessel until the ship became convinced the submarine had somehow escaped. Psychological studies later showed that crewmen transferred to the submarine after the event were never accepted as part of the team. Later, US naval policy was changed so that after events of such psychological trauma, the crew would be dispersed to new assignments. Rehabilitation of survivors becomes extremely difficult when entire nation has experienced such severe traumas as war, genocide, torture, massacre, etc. Treatment is hardly effective when everybody is traumatized. Trauma remains chronic and would reproduce itself as long as social causes are not addressed and perpetrators continue to enjoy impunity. The whole society may suffer from an everlasting culture of pain. During the Algerian War, Frantz Omar Fanon found his practice of treatment of native Algerians ineffective due to the continuation of the horror of a colonial war. He emphasized about the social origin of traumas, joined the liberation movement and urged oppressed people to purge themselves of their degrading traumas through their collective liberation struggle. He made the following remarks in his letter of resignation, as the Head of the Psychiatry Department at the Blida-Joinville Hospital in Algeria:
"If psychiatry is the medical technique that aims to enable man no longer to be a stranger to his environment, I owe it to myself to affirm that the Arab, permanently an alien in his own country, lives in a state of absolute depersonalization." Inculcation of horror and anxiety, through widespread torture, massacre, genocide and similar coercive measures has happened frequently in human history. There are plenty of examples in our modern history. Tyrants have always used their technique of "psychological artillery" in an attempt to cause havoc and confusion in the minds of people and hypnotize them with intimidation and cynicism. The result is a collective trauma that will pass through generations. There is no magic formula of rehabilitation. Collective trauma can be alleviated through cohesive and collective efforts such as recognition, remembrance, solidarity, communal therapy and massive cooperation.
