ADCYAP1R1 and post-traumatic stress disorder: They also found that women carrying the ADCYAP1R1 rs2267735 CC genotype showed decreased ADCYAP1R1 mRNA expression, increased PTSD symptom severity, increased dark-enhanced startle response, and increased amygdala and hippocampal activity in response to viewing threatening face stimuli [64–66, 89].