ADCYAP1 and psychiatric disorder: Several lines of evidence support that PACAP−/− mice are regarded as an animal model of psychiatric conditions (Hashimoto et al. 2001, 2007, 2009, 2010; Tanaka et al. 2006; Hatanaka et al. 2008) and that PACAP signaling might contribute to the pathogenesis of certain psychiatric disorders (Hashimoto et al. 2007, 2010).