A friendly version of the Trier Social Stress Test does not activate the HPA axis in healthy men and women

The trier social stress test (TSST) is a well-established laboratory stressor leading to a robust activation of the hypothalamus-pituitary-adrenal (HPA) axis. Existing control conditions are often not adequate to investigate participants' behavior during the situation as participants are often left alone in the room. This present study aimed to evaluate a friendly version of the TSST as control condition, the friendly-TSST (f-TSST). We expected that the f-TSST would not activate the HPA axis or increase the negative affect (NA). Forty-eight healthy male and female students (24 males) aged between 18 and 30 years were randomly exposed to either the TSST or the f-TSST. The latter features a similar structure and similar cognitive demands as in the TSST, and a social interaction with a committee. The main difference lies in the friendly and warm behavior of the committee opposed to the neutral and reserved behavior in the TSST, typically inducing social-evaluative threat. Salivary cortisol, salivary α-amylase (sAA), and affect were measured to evaluate the stress response to the respective procedure. As expected, the f-TSST neither activated the HPA axis nor increased the NA. The TSST by contrast led to an increase in both measures. A comparable and significant increase in the sAA-concentrations occurred in both conditions. The f-TSST could be useful as a standardized control condition for future stress studies. On a conceptual level our data indicate that mere social performance in the absence of social-evaluative threat and performance pressure does not activate the HPA axis.