Neurochemical pain research indicates that anticipatory anxiety, also associated with negative expectations, activates at least 2 independent pathways, namely the hypothalamus–pituitary–adrenal (HPA) axis, which controls reactions to stress,68 and the cholecystokinin (CCK-ergic) system, which is involved in the regulation of nociception, anxiety, and memory.37 In this nocebo pain model, the HPA axis is activated by nocebo suggestions and results in anticipatory anxiety. Here, CCK is linked to Anxiety.