Salivary alpha-amylase response following repeated psychosocial stress in patients with panic disorder.

BACKGROUND This study examined autonomic responses (salivary alpha-amylase, sAA; heart rate, HR) to repeated psychosocial stress as a candidate mechanism linking autonomic hyper-arousal and sensitization to the occurrence of panic disorder (PD). METHODS Thirty-three patients with PD and 34 healthy controls were exposed to the Trier Social Stress Test (TSST) twice on consecutive days. RESULTS sAA changes were comparable between PD and controls on both testing days with overall decreasing sAA responses (delta) on day two. In contrast, HR delta increased on day two in both groups. This sensitization was driven by female controls while male PD showed most pronounced HR changes to the first TSST. CONCLUSIONS Overall, a general autonomic hyper-arousal in PD could not be confirmed. In contrast, sAA responses slightly habituated to repeated stress. Whether sAA findings mirror assumed habituation effects of repeated stress exposure on normalizing autonomic reactivity remains to be investigated in longitudinal studies.