2. Examination of the extent to which early cortisol administration influences the relationship between preexisting and trauma-related factors and psychophysiological responses to trauma. In particular, as lifetime incidence of psychopathology, prior trauma exposure, and injury severity have been associated with increased risk for PTSD, we will examine whether this relationship is weakened in patients receiving the cortisol regimen. Due to budgetary constraints of the R34 mechanism and the exploratory nature of the proposed research, we will not be able to recruit enough participants to sufficiently examine this objective, and it is thus considered a secondary aim. However, results will be used to strengthen and guide the design of a subsequent R01 proposal.