GSTM1 and colitis: CBT did not significantly influence disease activity as measured by disease activity indices at 24 months (Crohn’s Disease Activity Index (CDAI), p = 0.92; Simple Clinical Colitis Activity Index (SCCAI), p = 0.88) or blood parameters (C-reactive protein (CRP), p < 0.62; haemoglobin (Hb), p = 0.77; platelet, p = 0.64; white cell count (WCC), p = 0.59) nor did CBT significantly affect mental health, coping or quality of life (all p > 0.05).