The effects of initial trauma exposure on the symptomatic response to a subsequent trauma

The effect of initial trauma on the symptomatic response to a subsequent trauma was investigated in a cross-sectional study of urban bus drivers. Comparisons were made among 175 drivers who had developed either high or low symptoms of post-traumatic stress disorder (PTSD) as a result of the initial trauma, and a third group exposed to only a single trauma. The group with high levels of PTSD symptoms after the initial trauma reported high PTSD symptoms for a subsequent trauma (75%) significantly more often than the other two groups who did not differ from each other (Low PTSD symptoms group 49%, No prior trauma group 41%). These results suggest that unless trauma exposure leads to significant PTSD symptoms, it is not a risk factor for high PTSD symptoms after exposure to a subsequent traumatic event.