Longitudinal relationships between self‐efficacy, post‐traumatic distress and salivary cortisol among motor vehicle accident survivors

The present study tested if post‐traumatic distress following a motor vehicle accident (MVA) and MVA‐related self‐efficacy beliefs were associated with diurnal salivary cortisol in the early post‐traumatic period. Cortisol was collected upon awakening and at 1, 4 and 12 h after waking. Collection days were 1 week, 1 month and 3 months after MVA. A total of 30 participants provided their cortisol samples across all measurement points. Two methods for computing the area under the cortisol curve were used. Higher post‐traumatic distress at 1 month predicted lower cortisol area under the curve (AUC) with respect to increase (AUC I , reflecting changes in cortisol secretions during daytime) at 3 months. AUC with respect to ground (AUC G , reflecting total cortisol release during daytime), measured at 1 month after trauma, predicted higher post‐traumatic distress at 3 months. The results showed that self‐efficacy at 1 week indirectly predicted 3‐month AUC I through 1‐month post‐traumatic distress. These findings highlight the importance of self‐efficacy and post‐traumatic distress in explaining longitudinal diurnal patterns of cortisol secretion after trauma. Copyright © 2011 John Wiley & Sons, Ltd.