Anxiety-depression interaction and somatic symptoms in functional gastrointestinal disorders: a retrospective cross-sectional study from gastroenterology outpatient clinics.

Abstract

This study aimed to explore the psychosomatic state of patients with functional gastrointestinal disorders (FGIDs), with the hypothesis that depression and anxiety are closely associated with somatic symptoms in patients with FGIDs. Retrospective cross-sectional study. The study was conducted in gastroenterology outpatient clinics. The analysis included 655 patients with FGIDs treated between March 2021 and December 2024. There were no interventions in this observational study. The primary outcome measure was the somatisation subscale score of the Symptom Checklist-90 (SCL-90-SOM). Secondary outcome measures included scores of the Self-Rating Anxiety Scale (SAS) and the Self-Rating Depression Scale (SDS). Heart rate variability (HRV) was also measured. Patients with FGIDs demonstrated relatively high SAS and SDS scores. Multivariable linear regression showed that female gender and higher SAS score were associated with higher SCL-90-SOM scores after adjustment for available covariates. SDS score showed a negative coefficient after adjustment for SAS, which may reflect adjustment-related suppression or symptom-scale overlap rather than a protective effect of depressive symptoms. A statistically significant interaction between SAS and SDS on somatic symptoms was observed using standardised variables (B=0.042, 95% CI 0.018 to 0.067, <i>P</i> _interaction<0.001). Among patients with FGIDs in this single-centre outpatient sample, anxiety symptoms were strongly associated with higher somatic symptom burden. Depressive symptoms modified the association between anxiety and somatic symptoms in the interaction model. However, interpretation is limited by the cross-sectional design, possible symptom-scale overlap and residual confounding. These findings support further prospective studies and suggest that assessment of co-occurring anxiety and depressive symptoms may be clinically relevant in FGID care.