The concept of psychological trauma was recognized in the 19th century in relation to industrial accidents and war-related syndromes. Shellshock was recognized as a major source of casualties in World War I. Combat fatigue and psychiatric decompensation were recognized as resulting from combat stresses in World War II. However, psychological trauma was still perceived in lesser terms than physical trauma. The development of the concept of Post-Traumatic Stress Disorder (PTSD) as a psychiatric diagnosis has appeared from DSM III in 1980 and subsequently evolved to DSM III-R and DSM IV. Inherent in the conceptions of PTSD is the definition of the stressor criterion--Criterion A--the actual psychological trauma that was experienced by the person diagnosed with PTSD. Both of the following must be present: (1) the person experienced, witnessed, or was confronted with an event or events that involved the actual or threatened death, or serious injury, or a threat to the physical integrity, of self or others; and (2) the person’s response involved intense fear, helplessness, or horror. Potentially traumatic events are frequent in the United States population sample, as well as Australia. The trauma with the highest likelihood of leading to PTSD was rape. Others were, for men, combat exposure, childhood neglect, and childhood physical abuse; for women, sexual molestation, physical attack, being threatened with a weapon, and childhood physical abuse. For the majority of people, any distress and impairment that may initially occur will settle over time. A number of factors may contribute to the outcome of PTSD, including exposure to trauma at an early age, and early separation (from parents). Severity of the potentially traumatic experience is a significant contributing factor. Severity can be identified both through the individual’s perception and description of the experience, and from the objective facts, as provided by others. 23 endnotes