Background Inflammatory bowel diseases (IBD), which are associated with a high disease burden, are also reported to be accompanied by a high prevalence of psychiatric disorders. However, the literature on IBD and psychiatric disorders has not been reviewed. Methods This systematic review followed the PRISMA guidelines, and its protocol was registered at PROSPERO (ID: CRD42020214359). PubMed, Embase and PsycINFO were consulted for the literature search. Studies reporting on diagnosed psychiatric disorders in IBD were included. Pooled prevalence rates were calculated using random effects meta-analyses. Study quality was assessed using the Newcastle-Ottawa Scale (NOS). Results Sixty-nine studies were identified with an average cohort size of 60,114 patients. Pooled prevalence rates were: mood disorders, 10% (95% CI=7%; 15%); anxiety disorders, 12% (95% CI=8%; 18%); substance misuse, 3% (95% CI=1%; 7%); psychotic disorders, 2% (95% CI=1%; 4%); behavioral disorders, 1% (95% CI=0%; 3%); personality disorders, 3% (95% CI=1%; 10%); developmental disorders, 1% (95% CI=0%; 3%); behavioral and emotional disorders with onset usually during childhood, 1% (95% CI=1%; 3%). All analyses had high statistical heterogeneity (I2 > 99%). Seven studies reported an increased risk of suicide in IBD patients compared to controls. Conclusion The prevalence of psychiatric comorbidities was high (11- 82%) in patients with IBD and was higher than in the background population. Addressing mental health problems in patients with IBD can improve their adherence to treatment and the somatic disease course and, consequently, reduce morbidity and mortality.

Objectives: The aim of this study was to investigate a possible association between extraintestinal manifestations (EIM) and a more severe disease course in pediatric onset inflammatory bowel disease (pIBD). Methods: This study compares the disease course of pIBD patients (IBD diagnosis <15 years of age) with and without EIM in a population-based cohort from Denmark. Patients diagnosed with pIBD between 1998 and 2008 were included in the study and followed until December 31, 2014. Data on phenotype, treatment, relapses, and the temporal relationship between IBD relapses and activity of EIM were collected at end of follow-up by manual revision of patient charts. Results: Of 333 pIBD patients, 14 (4.2%) had EIM at time of diagnosis and 47 (14.1%) developed EIM during follow-up. Median follow-up time was 9.6 years for patients with EIM and 8.8 years for patients without. In ulcerative colitis, EIM were associated with an increased risk of biological treatment and surgery (hazard ratio: 2.6; 95% confidence interval [CI]: 1.3–5.5, P = 0.008 and 2.9 [95% CI: 1.1–7.7, P = 0.03], respectively). In Crohn disease, EIM were associated with an increased relapse rate (1.3 [95% CI: 1.1–1.5], P = 0.001). Lastly, we found a positive temporal relationship between relapse of IBD and EIM activity. Conclusion: The presence of EIM is associated with a more severe disease course in pIBD. This should be considered when deciding treatment options, as a more aggressive treatment approach could be warranted in patients with EIM. However, prospective studies are needed to fully evaluate this.

Aim To estimate psychiatric comorbidity in childhood onset immune‐mediated inflammatory diseases (IMID). Methods The PRISMA guidelines were followed, and the protocol was registered at Prospero (ID: CRD42021233890). Literature was searched in PubMed, PsycINFO and Embase. Original papers on prevalence rates of diagnosed psychiatric disorders and/or suicide in paediatric onset inflammatory bowel disease (pIBD), rheumatic diseases (RD) and autoimmune liver diseases were selected. Pooled prevalence rates of psychiatric disorders (grouped according to ICD‐10 criteria) within the various IMID were calculated using random‐effects meta‐analysis. Risk of bias was evaluated by the Newcastle‐Ottawa scale. Results Twenty‐three studies were included; 13 describing psychiatric disorders in pIBD and 10 in RD. Anxiety and mood disorders were mostly investigated with pooled prevalence rates in pIBD of 6% (95% confidence interval (CI): 4%–9%) and 4% (95%CI: 2%–8%), respectively, in register‐based studies, and 33% (95%CI: 25%–41%) and 18% (95%CI: 12%–26%), respectively, in studies using psychiatric assessment. In RD, rates were 13% (95%CI: 12%–15%) for anxiety disorders and 20% (95%CI: 15%–26%) for mood disorders based on psychiatric assessment. Conclusion Anxiety and depression are commonly reported in childhood onset IMID. Physicians should be attentive to mental health problems in these patients as they seem overlooked.