The relationship between acute stress disorder and posttraumatic stress disorder in traffic accident victims. Thesis Department of Psychology, Aarhus University.

Acute stress disorder (ASD) has been an official diagnosis for almost a decade. During this period, a growing number of studies have shown that ASD predicts a significant part of those who develop posttraumatic stress disorder (PTSD). During the same period, research on psychological consequences of traffic accidents has greatly increased. These studies have shown that one in four traffic accident victims are at risk of developing PTSD, which is a potentially disabling disorder. The main objectives of the present thesis was: 1) to increase the knowledge of psychological consequences of traffic accidents by assessing what variables were predictive of PTSD in traffic accident victims, and 2) to evaluate the ASD diagnosis through assessment of predictor variables and the ability of ASD to predict PTSD. The objectives were achieved through a prospective Danish study on traffic accident victims treated at the emergency room after their accident and a prospective Swiss study on hospitalised accident victims. Both studies consisted of two assessments: the first within the first month after the accident and the second 6-8 months after the accident. From the Swiss study only cross-sectional results from the initial assessment will be reported in this thesis. ASD was assessed in both studies achieving an incidence of 28% in the Danish study and 4% in the Swiss study. The following predictor variables for ASD were found: Stay at an intensive care unit; a psychiatric diagnosis pre-accident; a low Sense of Coherence; threat of death or fear during the accident; appraisal of the accident as severe; appraisal of the accident as preventable by others; appraisal of the future physical recovery as less optimistic; experience of pain; gender (female); dissatisfaction with the level of social support received. PTSD was assessed in the Danish study and an incidence rate of 17% was found. The following predictor variables for PTSD were found: a high acute stress disorder score and a low satisfaction with received support. Low quality of life was further associated with the development of PTSD; specifically being a male traffic accident victim and reporting considerable mental impairment was associated with the development of PTSD. Although ASD symptom level was the strongest predictor of PTSD only half the PTSD diagnoses were preceded by an ASD diagnosis. The results, their clinical implications, and justification of existence of the ASD diagnosis are discussed. (Author/publisher)