CRHR1 and Anxiety: Single nucleotide polymorphisms (SNPs) such as rs110402 (CRHR1 gene), rs3800373 (FKBP5 gene), and rs2289656 (NTRK2 gene) have been linked to physiological mechanisms involving stress response and activation of the hypothalamic–pituitary–adrenal (HPA) axis, which contributes to anxiety and stress regulation.