Defining Potentially Traumatic Events

The posttraumatic stress disorder (PTSD) diagnosis was introduced 40 years ago in DSM-III, and controversy has existed ever since over what constitutes a criterion A stressor or a potentially traumatic event (PTE). This controversy was compounded by the radically different approach taken by the World Health Organization in defining PTSD and complex PTSD in the 11th revision of the International Classification of Diseases. These PTE definitions have considerable research, clinical, and legal implications because exposure to a qualifying PTE is a necessary, but not sufficient, condition to meet diagnostic criteria for PTSD. This chapter reviews the history of criterion A, essential elements of assessing PTE exposure, conditional risk of PTSD associated with specific PTEs, and situational and demographic variables likely to increase risk of PTSD. Significant attention is given to controversies surrounding criterion A and qualifying PTEs, as well as limitations of extant research. Recommendations are included for future research and clinical assessment with particular emphasis on the importance of comprehensive assessment that maximizes detection of criterion A PTE exposure and PTSD assessment strategies that capture the effects of exposure to more than one criterion A stressor.