Patients with irritable bowel syndrome, regardless of subtype, show higher levels of depression and anxiety compared with healthy controls, according to the results of a meta-analysis performed by the Brain-Gut Axis Research Group of the Korean Society of Neurogastroenterology and Motility.
Among IBS subtypes, patients with constipation-predominant IBS (IBS-C) showed the highest levels of both depression and anxiety.
“Knowledge of IBS’s correlation with psychiatric disorders would enhance understanding and treatment of IBS patients, as psychological distress could exacerbate symptoms, negatively affect treatment outcomes, and affect doctor-patient relationships,” the investigators wrote. “The aim of this meta-analysis was to compare depression and anxiety levels between IBS patients and healthy controls, also considering IBS subtypes and patient gender.”
They reviewed comparative studies of depression and anxiety in adults with IBS vs. healthy controls published from January 2000 to July 2016, and included 27 studies in their analysis, which involved 2,293 IBS patients and 4,951 healthy controls.
IBS patients showed significantly higher overall levels of depression and anxiety compared with healthy controls, with a pooled standardized mean difference (SMD) of 0.76 (95% CI, 0.62-0.9) for depression and 0.84 (95% CI, 0.67-1.01) for anxiety.
Analysis by IBS subtype showed significantly higher levels of both depression and anxiety across all subtypes (P < .001). IBS-C patients showed the highest levels, with SMDs of 0.83 for depression and 0.81 for anxiety, followed by patients with diarrhea-predominant IBS (IBS-D; 0.73 and 0.65) and IBS patients with mixed bowel habits (IBS-M; 0.62 and 0.75).
A possible explanation for the highest levels of depression and anxiety in IBS-C patients “is a change in the intestinal serotonin (5-hydroxytryptamine, 5-HT) system,” the investigators wrote. “Excess 5-HT could contribute to diarrhea through the 5-HT receptor; moreover, increased postprandial release of 5-HT in patients with IBS-D has been reported. On the other hand, the IBS-C subtype may be considered an imbalance of 5-HT secretion, and high levels of depression and anxiety in IBS-C subtype may be associated with low responsiveness of 5-HT in both the central and peripheral regions.”
While the studies showed significant heterogeneity, meta-regression analysis showed that study region and type of depression/anxiety questionnaire explained this. The investigators also noted they were unable to directly compare male and female patients, and that “the gender effect in IBS with psychological distress should be evaluated in prospective studies.” – by Adam Leitenberger
Disclosures: The researchers report no relevant financial disclosures.