In an older study, the results showed a substantial increase in serum cortisol levels in 10 IBS patients compared to 10 healthy controls despite identical CRH levels (from baseline to peak at 60 min, controls: 13.6 (1.2) mg/dL to 28.9 (1.3) mg/dL; IBS patients: 13.6 (1.6) mg/dL to 30.2 (1.8) mg/dL; p < 0.001) [55]. This evidence concerns the gene CRH and irritable bowel syndrome.