Background: Exposure to a traumatic event leads to posttraumatic stress disorder (PTSD) in 10-20% of exposed individuals. Predictors of risk are needed to target early interventions to those who are most vulnerable. The objective of the study was to test whether a noninvasive mobile device that measures a physiological biomarker of autonomic nervous system activation could predict future PTSD symptoms.
Methods: Skin conductance response (SCR) was collected during a trauma interview in the emergency department within hours of exposure to trauma in 95 individuals. Trajectories of PTSD symptoms over 12 months post-trauma were identified using Latent Growth Mixture Modeling.
Results: SCR was significantly correlated with the probability of being in the chronic PTSD trajectory following trauma exposure in the ED (r=0.489, p<0.000001). Lasso regression with elastic net was performed with demographic and clinical measures obtained in the ED, demonstrating that SCR was the most significant predictor of the chronic PTSD trajectory (p<0.00001).
Conclusions: The current study is the first prospective study of PTSD showing SCR in the immediate aftermath of trauma predicts subsequent development of chronic PTSD. This finding points to an easily obtained, and neurobiologically informative, biomarker in emergency departments that can be disseminated to predict the development of PTSD.