In 1980 the American Psychiatric Association (APA) added the diagnosis of post-traumatic stress disorder (PTSD) into the Diagnostic Statistical Manual of Mental Disorders (DSM-III). This is a manual widely used by psychiatrists to diagnose mental illnesses. It was a landmark moment for psychiatry. The inclusion of PTSD provided official recognition to a disorder which had been without a clear definition for decades.

High casualties and death tolls during WWI were culturally accepted as ‘doing one’s duty’ for the greater good of the nation. As the century wore on, the public became less tolerant of casualties in war and it became a political issue. The Vietnam War had few psychiatric casualties compared to the preceding wars. But stories of soldiers suffering from psychological disorders reached the media. They fuelled public resentment towards an already unpopular war. Anti-Vietnam lobbyists were able to use this momentum to pressure the APA into defining PTSD.