Cumulative Effect of Psychological Alterations on Gastrointestinal Symptom Severity in Irritable Bowel Syndrome

Psychological alterations are common and considered important for symptom generation in irritable bowel syndrome (IBS). However, the possible cumulative effect of having multiple psychological alterations on gastrointestinal (GI) symptom severity in IBS is largely unknown.

Patients with IBS (Rome IV) completed validated questionnaires assessing GI symptoms (Gastrointestinal Symptom Rating Scale, IBS version and IBS Severity Scoring System), personality traits (Big Five), posttraumatic stress and psychological alterations, anxiety (Generalized Anxiety Disorder 7-item scale and State-Trait Anxiety Inventory), depression (Patient Health Questionnaire, 9-item version), fatigue (Multidimensional Fatigue Inventory), pain catastrophizing, somatization (Patient Health Questionnaire, 12-item version), stress (Perceived Stress Scale), and GI-specific anxiety (Visceral Sensitivity Index). Of the 18 possible psychological factors, those with significant associations with GI symptom severity, corrected for multiple comparisons, were identified. The associations between increasing number of psychological alterations (validated cutoff values or uppermost tertile) and the severity of GI symptoms were analyzed with linear trend analyses.

In total, 106 patients with IBS (Rome IV criteria) were included (72 [68%] women, median age of 35 [interquartile range: 26-45] years). Psychological alterations were common and overlap among these factors were frequently seen. Five psychological factors (physical fatigue, GI-specific anxiety, perceived stress, pain catastrophizing, and trait anxiety) demonstrated significant, noncollinear associations with GI symptom severity. With increasing number of these psychological alterations, a gradual increase was seen in the overall severity of GI symptoms (Gastrointestinal Symptom Rating Scale, IBS version: partial η = 0.268, P < 0.001; IBS Severity Scoring System: partial η = 0.219, P < 0.001, both large effect sizes).

Distinct associations were seen between the severity of GI symptoms and individual, as well as an increasing number of psychological alterations. This highlights the importance of understanding different psychological alterations for the disease burden in IBS (visual abstract, Supplementary Digital Content 1, http://links.lww.com/AJG/B756).