ADCYAP1R1 and major depressive disorder: In a similar context, human studies revealed that the PACAP/PAC1 receptor upregulated the production of the protein DISC1 (shown to be disrupted in schizophrenia) [203], in addition to demonstrating significant associations between SNPs in the PACAP gene and depression [204] and the PAC1 receptor polymorphism in PTSD in female patients [205,206].