As it was widely recognized that inadequate and/or prolonged response to stressors may result in psychiatric disorders (Charmandari et al. 2005), impairment of the stress response by altered PACAP signaling systems may partly relate to certain psychiatric conditions and this possibility warrants further investigation in the PVN as corticosterone responses were attenuated in PACAP−/− mice. Here, ADCYAP1 is linked to psychiatric disorder.