Trait Anxiety Accentuates the Cortisol Awakening Response

The present study examined the relationship between trait anxiety and multiple indices of the cortisol awakening response (CAR) in a group of 79 healthy university students. Saliva samples were collected from participants 4 times (0, 15, 30 and 45 minutes post-awakening) immediately after waking up in the morning to determine two indices of the CAR: AUC and MnInc. The former refers to the cortisol curve with reference to zero and the latter dynamic increase of cortisol from immediately after waking to the last post-awakening sample. To eliminate the potential contamination of data by non-adherence among participants, data from those who reported to provide the first saliva sample later than 10 minutes after waking were excluded from analyses. Data from eleven participants were excluded by using this criterion. Results showed that higher trait anxiety was associated with a larger MnInc. The selective effect of trait anxiety on MnInc but not AUC is consistent with prior findings showing that chronic stress increases rise in cortisol in the post-awakening period. This specific index of CAR may serve as an objective benchmark for the effectiveness of anxiolytic psychological interventions.