Chronic stress models, including repeated variate stress and social defeat, robustly increase PACAP, PAC1, BDNF, and TrkB expression in males, correlating with heightened anxiety-like behavior [69, 70], while females show blunted responses, potentially due to estrogenic buffering or differential glucocorticoid signaling [71, 72]. This evidence concerns the gene NTRK2 and Anxiety.