Risk of schizophrenia in people with coeliac disease, ulcerative colitis and Crohn's disease: a general population‐based study

Summary Background Recently, interest has been revived in whether people with coeliac disease, in contrast to other inflammatory gastrointestinal diseases, have an increased risk of schizophrenia. Aim To compare the risk of schizophrenia in people diagnosed with coeliac disease, ulcerative colitis and Crohn's disease with the general population. Methods We used data from the UK General Practice Research Database. People with coeliac disease, Crohn's disease and ulcerative colitis were matched individually with five age‐, sex‐ and general practice‐matched controls. The prevalence of schizophrenia was calculated and compared between disease groups and their respective controls. We calculated odds ratios for schizophrenia using conditional logistic regression adjusting for smoking status. Results In people with coeliac disease, Crohn's disease and ulcerative colitis the prevalence of schizophrenia was 0.25%, 0.27% and 0.24%, respectively, compared with a general population prevalence of 0.37%. The adjusted odds ratios showed no association between schizophrenia and gastrointestinal disease (coeliac disease vs. controls 0.76, 95% CI: 0.41–1.4; Crohn's disease vs. controls 0.74, 95% CI: 0.44–1.3; ulcerative colitis 0.71, 95% CI: 0.44–1.1). Conclusions Contrary to recent findings we found no evidence of an increased risk of schizophrenia in people with coeliac disease compared with the general population.