Severity of traumatic injuries predicting psychological outcomes: A surprising lack of empirical evidence

- We examined a medically validated measure of event severity in patients admitted to a Level I Trauma Center.
- We examined multiple outcome measures at baseline, 3, 6, and 12 months post-injury.
- We found that event severity was not significantly related to any of the outcomes at baseline, 3, and 6 months post-injury.
- We found a very weak effect of event severity at 12 months post-injury.
- We conclude that despite widespread belief to the contrary.
- The empirical evidence does not support a relationship between event severity and likelihood of elevated posttraumatic stress symptoms.

Despite widespread beliefs that trauma severity is related to levels of posttraumatic stress symptoms (PTSS), the empirical evidence to support such beliefs is lacking. In the current study we examined Injury Severity Score (ISS), a medical measure of event severity for physical injuries, in a sample of 460 patients admitted to a Level 1 Trauma Center. Results revealed no significant relationship between ISS and PTSS, depression, pain, and general physical and mental health at baseline, three months, and six months post-injury. However, at 12 months post-injury, ISS significantly predicted depression, pain, and physical health, but was unrelated to PTSS. The effect sizes of these relationships were small and would not remain significant if any adjustments for multiple comparisons were employed. We conclude that the relationship between ISS and PTSS is, at best, weak and inconsistent. The results are discussed in the broader picture of event severity and psychological outcomes.