Journal of Traumatic Stress June 2012, 25, 280–287 Differences in Posttraumatic Stress Reactions Between Witnesses and Direct Victims of Motor Vehicle Accidents Marlies Tierens, 1 Sarah Bal, 1 Geert Crombez, 2 Tom Loeys, 3 Inge Antrop, 1 and Dirk Deboutte 4 1 Department of Psychiatry and Medical Psychology, Research Unit of Child and Adolescent Psychiatry, Ghent University Hospital, Ghent, Belgium 2 Department of Experimental Clinical and Health Psychology, Ghent University, Ghent, Belgium 3 Department of Data Analysis, Ghent University, Ghent, Belgium 4 Collaborate Antwerp Psychiatry Research Institute, Antwerp University, Antwerp, Belgium; Department of Psychiatry and Medical Psychology, Research Unit of Child and Adolescent Psychiatry, Ghent University Hospital, Ghent, Belgium The present study describes posttraumatic stress reactions in young witnesses of motor vehicle accidents (MVAs). This study investigated (a) whether witnesses of MVAs report fewer trauma symptoms than direct victims, but more than adolescents who were never exposed to an MVA; and (b) whether individual differences in sex, negative appraisal, avoidant coping, and social support account for variability in trauma symptoms beyond status as a witness as compared to a victim. Self-report data came from a community-based sample of 3,007 adolescents with an average age of 14.6 years and comprising 53% boys. Compared to direct victims of an MVA in which someone was injured, witnesses of MVAs with injury reported significantly less internalizing symptoms, such as symptoms of posttraumatic stress (d = 0.25), fear (d = 0.21), and depression (d = 0.17). Compared to adolescents who were never exposed to an MVA with injury, witnesses reported significantly more externalizing symptoms (d = 0.24). In multiple regression analyses the significant difference between witnesses and victims disappeared when sex, other stressful events, appraisals, and coping were added to the model. These findings suggest that adolescent witnesses, as well as direct victims, may be at risk for posttraumatic reactions. Posttraumatic reactions are not limited to direct victims. Ac- cording to Criterion A of the diagnosis for posttraumatic stress disorder (PTSD) in the Diagnostic and Statistical Manual of Mental Disorders (4th ed., text rev.; DSM-IV-TR; American Psychiatric Association, 2000) witnesses also may suffer from PTSD. Although there is emerging evidence for posttraumatic stress reactions in direct victims of motor vehicle accidents (MVAs; Olofsson, Bunketorp, & Andersson, 2009), no study of which we are aware has investigated the psychological con- sequences in young witnesses of an MVA. Research on witnesses of single, noninterpersonal trauma in- cidents other than an MVA (e.g., air crash or fall accidents) sug- The study was financially supported by the Research Foundation - Flanders (Code G.0005.08); Levenslijn-Kinderfonds administered by Koning Boudewi- jnstichting. The authors like to thank the schools and students who participated in the study, Davy Coppens and Hanna Delefortie for their participation in data gathering, and Dr. K. De Corte and Dr. M. Van Hemelrijck for their revision of the manuscript. Correspondence concerning this article should be addressed to Marlies Tierens, Research Unit of Child and Adolescent Psychiatry, Ghent Uni- versity Hospital, De Pintelaan 185, 0K12F, 9000 Gent, Belgium. E-mail: Marlies.Tierens@UGent.be Copyright C  2012 International Society for Traumatic Stress Studies. View this article online at wileyonlinelibrary.com DOI: 10.1002/jts.21692 gests that witnessing a severe stressor can elicit posttraumatic stress symptoms (PTSS) or other trauma symptoms (Cuffe et al., 1998; Goncalves, Lima, & Pinto, 2006; Slottje et al., 2008). For example, Kim et al. (2009) studied the reactions of 1,394 elementary school children 6 months after the occur- rence of a serious accident at their school. The children who witnessed the accident showed more PTSS, anxiety, and de- pression compared to those who did not. A review concluded that although the indirect experience of a traumatic event may result in fewer or less severe symptoms than direct trauma, it may still lead to chronic moderate levels of distress (Lerias & Byrne, 2003). Although direct or indirect exposure to a traumatic event is a necessary condition for the development of trauma symp- toms, it is not sufficient to explain the large variability in symp- toms. Studies have identified a range of risk and protective factors for the development of trauma symptoms. In contrast to a dose-response model, which states that direct exposure is more traumatizing than indirect exposure (Bowman, 1999; Petersen, Elklit, & Olesen, 2010), studies in young victims of traumatic events indicate that child characteristics such as sex, appraisals, and coping and environment characteristics such as social support account for more variance in trauma symptom development than the severity of the event (Bal, Crombez, De Bourdeaudhuij, & Van Oost, 2009; Ellis, Nixon, & Williamson, 280