ADCYAP1 and post-traumatic stress disorder: Moreover, genetic variants in the PACAP/PAC1 genes were associated with altered treatment efficacy in generalized anxiety disorder [37] and circulating PACAP levels were positively correlated with anxiety disorders [35, 36, 38], PTSD symptom severity, and diagnostic status [35] or intrinsic amygdala functional connectivity in PTSD [38].