CRH and post-traumatic stress disorder: In adult mice, social defeat stress has been associated with a decrease in methylation at the Crh promoter in the paraventricular nucleus.80 This finding is supported by studies that reported increased CRH levels in the cerebrospinal fluid and plasma of individuals with PTSD.81–83 In other studies, adult rodents and nonhuman primates that were deprived of their mothers during youth have shown increased CRH concentrations within and outside the hypothalamus and in the cerebrospinal fluid.35–37 These animals may exhibit hyperactive HPA axis and behavioral stress responses throughout life.