Abstract
BACKGROUND: Anxiety and depression are implicated as contributors to abdominal pain in pediatric irritable bowel syndrome (IBS) but is unclear if this pain is associated with other psychological factors. The study objective was to test if the impact of anxiety or depression on IBS symptom severity is mediated by somatization and/or pain catastrophizing. METHODS: We utilized baseline data from local pediatric IBS clinical studies. Through mediation analysis, we assessed whether somatization or pain catastrophizing mediated (either independently or combined) the separate relationships of anxiety or depression with IBS abdominal pain severity. KEY RESULTS: We analyzed 261 participants. All psychological factors were positively correlated with one another and IBS abdominal pain severity. The association of anxiety with IBS abdominal pain was mediated by both somatization and pain catastrophizing in individual analyses (each mediated standardized coefficient [β] 0.11, CI 0.05-0.18) and in multiple analysis (mediated standardized β 0.18, CI 0.09-0.27). The association of depression with IBS abdominal pain was also mediated by somatization (mediated standardized β 0.08, CI0.02-0.14) and pain catastrophizing (mediated standardized β 0.06, CI 0.01-0.11) in individual analyses and in multiple analysis (mediated standardized β 0.19, CI 0.04-0.19). CONCLUSIONS AND INFERENCES: Somatization and pain catastrophizing mediate the relationships between anxiety/depression and IBS abdominal pain severity. These findings suggest that somatization and pain catastrophizing may be better treatment targets than anxiety and depression. Clinicians should assess these psychological factors in pediatric IBS patients and refer for intervention to improve outcomes.