**1.2 The importance of assessing peritraumatic distress**

Among the indicators for posttraumatic stress disorder, peritraumatic distress is a good candidate for screening individuals at high risk of developing the disorder. Peritraumatic stress can enhance trauma-related memory and sensitize the neurobiological systems (Charney et al., 1993), which links to the development of posttraumatic stress disorder. Many clinical studies and a meta-analysis have shown that perceived threat to life is a predictor of posttraumatic stress disorder (Holbrook et al., 2001; Matsuoka et al., 2008; Ozer et al., 2003; Schnyder, Moergeli, Trentz et al., 2001) and psychiatric morbidity (Matsuoka et al., 2008; Schnyder, Moergeli, Trentz et al., 2001). Peritraumatic distress is also linked with posttraumatic growth, which Tedeschi & Calhoun (2004) define as the positive psychological change experienced as a result of the struggle with highly challenging life circumstances. They state that only psychologically 'seismic' events shake the assumptive world, which leads to posttraumatic growth. Accordingly, peritraumatic distress can be an indicator for posttraumatic growth. A better understanding of peritraumatic distress would be significant for both prevention, especially in emergency settings, and treatment of posttraumatic stress disorder.

The aim of this chapter is to elucidate the predictive usefulness of peritraumatic distress and to examine the future directions for prevention with a focus on the use of the Peritraumatic Distress Inventory, an assessment tool for peritraumatic distress.
